How to clone a Windows 11 disk: partition sizes, smaller SSDs and free tools

Read this before selecting a disk

Cloning copies a Windows installation from one disk to another. It can preserve the operating system, applications, accounts, boot files and recovery environment, which is splendid when replacing an ageing hard disk with an SSD. It can also erase the wrong disk with remarkable efficiency.

The destination disk will be overwritten. Before beginning:

• make a separate, tested backup of irreplaceable files;
• record the manufacturer, model, serial number and capacity of both disks;
• store the BitLocker recovery key somewhere other than the computer being cloned;
• prepare Windows 11 recovery or installation media;
• connect the laptop to power and disable sleep for the maintenance window;
• stop if the source disk is failing, clicking, disappearing or reporting read errors — recovery imaging needs a different strategy from an ordinary upgrade.

A clone is not a backup. If the source contains corruption, ransomware, an unwanted administrator or a deleted file, the clone usually contains the same problem in a faster enclosure.

This lab covers a normal Windows 11 migration on hardware you own or administer: SATA or NVMe source, GPT/UEFI boot and a healthy destination SSD. It gives separate instructions for a smaller destination because “500 GB” printed on two boxes does not guarantee that the disks contain the same number of sectors.

Choose the job before choosing the tool

These terms are often mixed together:

For a one-off SSD replacement, a whole-disk clone is simple. An image-first workflow is safer: create an image on a third external disk, verify it, then restore it to the new SSD. That gives you a recovery point if the direct clone fails or somebody discovers halfway through that Disk 1 was not the empty SSD after all.

The Windows 11 partition layout that should survive the trip

A typical UEFI Windows 11 system disk uses GPT and contains:

| EFI System | MSR | Windows (C:)                 | Windows RE |
| FAT32      |     | NTFS                         | NTFS       |
| boot files |     | Windows, apps and user data  | recovery   |

OEM machines may also contain diagnostics, factory-recovery or vendor utility partitions. Do not delete an unfamiliar partition merely because it has no drive letter. Identify it first.

Minimums versus sizes that remain useful

The table separates Microsoft's current deployment requirements from a sensible new target layout.

Microsoft's May 2026 UEFI/GPT deployment guidance recommends 990 MB as the minimum recovery partition for custom bare-metal layouts, with at least 250 MB free. That is a more useful design target than the absolute 300 MB partition floor. Allocating 1–2 GB costs little on a modern SSD and prevents many future WinRE update failures.

You may encounter a healthy older installation with a 100 MB ESP or a 500–700 MB recovery partition. Cloning it exactly can still boot. Do not shrink those partitions further. When rebuilding or deliberately resizing the layout, use the current guidance rather than perpetuating a partition that already has no breathing room.

Place Windows RE immediately after the Windows partition. Windows can then shrink or recreate the recovery area when a later recovery image needs more room. The drawback is that the recovery partition sits between C: and unused space on a larger target, which can prevent Disk Management from extending C:. Decide the final sizes before the clone rather than expecting every partition editor to tidy the layout automatically.

Inventory the source from Windows

Open Windows PowerShell as administrator and collect a read-only inventory:

Get-Disk |
  Select-Object Number, FriendlyName, SerialNumber, PartitionStyle,
    @{Name='SizeGiB';Expression={[math]::Round($_.Size / 1GB, 2)}}

Get-Partition -DiskNumber 0 |
  Select-Object PartitionNumber, DriveLetter, Type,
    @{Name='SizeMiB';Expression={[math]::Round($_.Size / 1MB, 0)}}, Offset

Get-Volume |
  Select-Object DriveLetter, FileSystemLabel, FileSystem,
    HealthStatus, SizeRemaining, Size

Replace disk number 0 if Windows is on another disk. Check the disk in Disk Management (diskmgmt.msc) as a second view.

Check the logical and physical sector size:

Get-PhysicalDisk |
  Select-Object FriendlyName, MediaType, HealthStatus,
    LogicalSectorSize, PhysicalSectorSize, Size

This matters when creating a fresh ESP: Microsoft's current minimum is 200 MB for 512n/512e storage and 300 MB for a 4Kn device.

Confirm the boot mode and recovery environment:

Confirm-SecureBootUEFI
reagentc /info

Confirm-SecureBootUEFI returns a Boolean on supported UEFI systems and can report that the cmdlet is unsupported on a legacy BIOS system. reagentc /info should show Windows RE as enabled and give its partition path.

Check BitLocker and the file system:

Get-BitLockerVolume |
  Select-Object MountPoint, VolumeStatus, ProtectionStatus, EncryptionMethod

chkdsk C: /scan

Do not start a clone while Windows reports file-system errors, a BitLocker conversion is in progress, or the source disk's health is questionable.

Can the data fit on a smaller SSD?

Four numbers matter:

1. the destination's actual sector capacity;
2. the end position of the last source partition;
3. the minimum shrink size Windows reports for C:;
4. the space used inside every partition that must be copied.

Free space on C: alone is not enough. A 1 TB source with 120 GB used can still have a recovery partition located near the end of the disk. A cloning tool that copies the source partition table may reject a 500 GB target because that final partition would fall outside the destination.

Ask Windows how far the NTFS volume can shrink:

Get-PartitionSupportedSize -DriveLetter C |
  Select-Object `
    @{Name='SizeMinGiB';Expression={[math]::Round($_.SizeMin / 1GB, 2)}},
    @{Name='SizeMaxGiB';Expression={[math]::Round($_.SizeMax / 1GB, 2)}}

Then inspect the target's real capacity:

Get-Disk |
  Select-Object Number, FriendlyName, SerialNumber,
    @{Name='SizeGiB';Expression={[math]::Round($_.Size / 1GB, 2)}}

Choose a final C: size that leaves room for:

• the ESP and MSR;
• 1–2 GB for Windows RE;
• any OEM or data partitions you genuinely need;
• at least 15–20 GB of ordinary operating headroom beyond current used data;
• the difference between advertised decimal gigabytes and the GiB shown by Windows.

For example, a 476.94 GiB target should not receive a layout totalling 476.94 GiB on paper. Leave alignment and growth margin. If 350 GiB is currently used on C:, a 380 GiB C: partition may technically fit but leaves an unhappy future. Remove or archive data first.

BitLocker: suspension is not decryption

Before changing boot components, store the recovery key through the organisation's approved process: Microsoft account, Microsoft Entra ID, Active Directory or an offline record. Do not put the only copy in a file on C:.

You can suspend the boot-time protectors:

Suspend-BitLocker -MountPoint 'C:' -RebootCount 0

This is useful during hardware and boot changes, but Microsoft explicitly notes that suspension does not decrypt the volume. The sectors remain encrypted; a clear key is temporarily available on the disk. An offline Linux cloning tool may still see an unsupported encrypted volume and fall back to sector-by-sector copying. That normally prevents shrinking to a smaller destination.

Use one of these plans:

• Same-size or larger target: a sector copy may be acceptable, provided the destination has at least as many sectors and you possess the recovery key.
• Smaller target: fully decrypt the Windows volume before shrinking, or use a Windows-aware cloning tool that explicitly supports the encrypted source and your required layout.
• Managed business device: follow the organisation's BitLocker escrow and change-control policy; do not silently decrypt company data.

To decrypt deliberately:

Disable-BitLocker -MountPoint 'C:'
Get-BitLockerVolume -MountPoint 'C:'

Wait until VolumeStatus reports fully decrypted before resizing or using a file-system-aware offline clone. Decryption removes at-rest protection during the maintenance window, so control physical access and re-enable encryption after verification.

Best free tools in 2026

Rescuezilla — best first choice for a graphical offline workflow

Rescuezilla is free, open source and presents backup, restore and clone operations through a graphical live environment. It can open Clonezilla images and includes tools such as GParted.

Use it when you want a clear interface, an image-first safety option and a straightforward whole-disk migration to an equal or larger target. Rescuezilla's own documentation says that restoring or cloning to a smaller disk still requires a workaround: resize the source partitions first with GParted or Windows. It does not currently promise an automatic “make everything fit” button.

Clonezilla Live — best free advanced tool

Clonezilla is free and open source, fast with supported file systems and very explicit about source and destination. It is excellent for technicians comfortable with a text interface.

Beginner mode normally refuses a destination smaller than the source. Expert option -icds disables that disk-size check. It does not shrink data or move an out-of-bounds partition; using it with a layout that does not fit can create an unusable clone. Option -k1 creates a proportional target partition table and -r resizes supported file systems, primarily useful when expanding a smaller image onto a larger disk. Pre-shrink and verify the smaller-target layout instead of treating those switches as wizardry.

Hasleo Disk Clone — easiest Windows-native freeware option

Hasleo Disk Clone is proprietary freeware rather than open source. The current vendor documentation lists Windows system migration, disk and partition cloning, partition-size adjustment and WinPE media creation. It is attractive when you want to clone from inside Windows or adjust the target layout graphically.

Do not confuse it with every feature of Hasleo Backup Suite Free: the vendor's current comparison table says the free Backup Suite does not include system-disk cloning, while the separate Hasleo Disk Clone product is advertised for that purpose. Confirm the current edition and business-use licence before standardising it in an organisation.

GParted Live — a partition editor, not the clone itself

GParted can move and resize NTFS partitions and is included in many rescue environments. Use it when the recovery partition must be moved or the offline source layout needs adjustment. Every move increases time and risk; create an image first.

Rufus and Ventoy — tools for the USB, not for the clone

Rufus is a free, open-source Windows utility for writing a bootable ISO to USB. It is the simplest recommendation for one rescue ISO. Ventoy installs a multi-boot loader to the USB; after that you copy ISO files onto its data partition. Ventoy is convenient for keeping Rescuezilla, Clonezilla and Windows installation media together, but the initial installation formats the selected USB and Secure Boot may require additional setup.

Prepare the bootable USB with Rufus

Use a blank USB stick of at least 8 GB. Everything on it will be erased.

1. Download Rescuezilla or Clonezilla only from the project's official site.
2. Download Rufus from rufus.ie; the portable executable needs no installation.
3. Verify the ISO hash against the value published by the project:

Get-FileHash "$env:USERPROFILE\Downloads\rescuezilla.iso" -Algorithm SHA256

1. Insert the empty USB and identify it before opening Rufus:

Get-Disk |
  Select-Object Number, FriendlyName, SerialNumber, BusType,
    @{Name='SizeGiB';Expression={[math]::Round($_.Size / 1GB, 2)}}

1. In Rufus choose the exact USB under Device, choose the downloaded ISO under Boot selection, and use the ISO's recommended UEFI-compatible settings. For a modern Windows 11 machine, boot the resulting entry in UEFI mode rather than a legacy or CSM entry.
2. Start the write only after checking the USB capacity and model again.
3. Eject and reconnect the USB, then confirm Windows can see its files.

The rescue USB is not the same as a Windows recovery drive. Prepare a second 8 GB or larger USB with Microsoft's Media Creation Tool, or create a Windows Recovery Drive using recoverydrive.exe. Microsoft warns that both processes erase the selected USB. Windows installation media gives you Startup Repair and bcdboot if the clone does not start.

Prepare the USB with Ventoy instead

Ventoy is useful for a technician's multi-tool USB:

1. back up the USB — Ventoy installation erases it;
2. run Ventoy2Disk.exe as administrator;
3. select the exact removable disk and enable Secure Boot support if required by your environment;
4. install Ventoy;
5. copy the Rescuezilla, Clonezilla and current Windows 11 ISO files to the large exFAT partition;
6. boot the computer from the UEFI Ventoy entry and choose the required ISO.

Test this on the actual hardware before the maintenance window. Secure Boot firmware varies, and some systems may require key enrolment or a different rescue image.

Prepare Windows before cloning

1. Update and restart cleanly

Finish pending Windows updates, restart, sign in once and confirm there is no pending BitLocker, firmware or storage operation.

2. Check disk and system health

chkdsk C: /scan
Get-PhysicalDisk |
  Select-Object FriendlyName, HealthStatus, OperationalStatus

If chkdsk reports repairs are required, make the independent backup first and schedule the appropriate repair. Do not use repeated chkdsk /r scans as a cure for physically failing storage.

3. Remove avoidable bulk

Empty temporary files and move large archives that need not live on the Windows disk. Hibernation can consume several gigabytes. If a smaller target requires the space, disable it temporarily:

powercfg /h off

This also disables Fast Startup. Restore it after the clone with powercfg /h on if your policy uses hibernation.

4. Shrink C: for a smaller destination

Use Disk Management's Shrink Volume or PowerShell after reviewing Get-PartitionSupportedSize. This sample previews a 180 GiB target size without making the change:

$desiredSize = 180GB
Resize-Partition -DriveLetter C -Size $desiredSize -WhatIf

If the preview matches the intended volume and the backup exists, repeat without -WhatIf:

Resize-Partition -DriveLetter C -Size $desiredSize

Do not copy 180GB blindly. Your size must exceed SizeMin, exceed the current data requirement with headroom, and leave all required partitions inside the destination boundary.

If Windows cannot shrink far enough, unmovable page, hibernation, shadow-copy or metadata files may be near the end of the volume. Remove hibernation, reduce temporary data and consider an offline resize after imaging. Do not randomly delete system files.

5. Shut down fully

shutdown /s /t 0

Connect the destination through a suitable NVMe or SATA enclosure, or install both disks internally. Confirm the enclosure supports the target sector size and capacity.

Clone with Rescuezilla: recommended graphical route

The safest sequence is image first:

1. Boot the Rescuezilla USB through the computer's one-time UEFI boot menu.
2. Select Backup and choose the Windows source disk by model, serial and capacity.
3. Include the ESP, MSR, Windows and recovery partitions; include OEM or data partitions only when required.
4. Save the image to a third external disk or trusted network share with adequate free space.
5. When complete, use Rescuezilla's verification feature if offered by the current release.
6. Select Restore, choose the saved image and then select the new SSD as the destination.
7. Review the final summary slowly. The destination is the disk that will be overwritten.
8. Restore and wait for completion without closing the lid or disconnecting storage.

For a direct clone, choose Clone, select the old Windows disk as source and the new SSD as destination, then review the exact models and capacities before proceeding.

For a smaller target, pre-shrink the partitions first. If Rescuezilla still reports that the destination is too small, stop. Do not improvise with a sector-copy option. Use the image plus GParted/Clonezilla expert workflow, or a Windows-aware cloning product that can lay out the smaller target explicitly.

Clone with Clonezilla: advanced route

For an equal or larger destination:

1. Boot Clonezilla Live in UEFI mode.
2. Choose Start Clonezilla.
3. Choose device-device for a direct disk clone.
4. Choose Beginner for a normal migration.
5. Choose disk_to_local_disk.
6. Select the source by model, serial and capacity.
7. Select the destination and confirm that it contains nothing required.
8. Let Clonezilla check the source file system when practical.
9. Review the complete command and confirmation screen before starting.

On a larger target, Clonezilla can retain the original sizes or use -k1 with -r to create a proportional partition layout and grow supported file systems. Proportional growth can waste space on EFI and recovery partitions, so a manually planned layout may be better.

For a smaller target, first ensure every partition and its end sector fit. Clonezilla's expert -icds option only skips the destination-size guard. The project itself labels it an expert option and warns that you must know the data fits. If you cannot prove that from the partition layout, do not use it.

First boot: disconnect the old disk

After cloning:

1. power the computer off;
2. disconnect or remove the source disk;
3. install the destination in the intended internal slot;
4. enter firmware setup and confirm UEFI mode and the new Windows Boot Manager entry;
5. boot Windows from the clone.

Disconnecting the source proves that the new disk contains its own boot files. It also avoids duplicate disk identifiers and the embarrassing situation where Windows appears to boot from the SSD while quietly relying on the old disk's ESP.

Do not erase the source yet. Keep it powered off until the clone has passed application, update, recovery and backup tests.

Validate the clone

In the cloned Windows installation run:

Get-Disk |
  Select-Object Number, FriendlyName, SerialNumber, PartitionStyle,
    @{Name='SizeGiB';Expression={[math]::Round($_.Size / 1GB, 2)}}

Get-Partition -DiskNumber 0 |
  Select-Object PartitionNumber, DriveLetter, Type, Size, Offset

chkdsk C: /scan
reagentc /info
Get-BitLockerVolume

Then verify:

• Windows Update completes and another restart succeeds;
• networking, audio, sleep and device drivers work;
• important applications and licences open normally;
• user files match the independent backup;
• Windows RE is enabled;
• the expected EFI, MSR, Windows and recovery partitions exist;
• C: has the planned capacity and free space;
• the backup application recognises the new disk;
• BitLocker protection is enabled again according to policy.

Check TRIM support for an SSD:

fsutil behavior query DisableDeleteNotify

For NTFS, a result of 0 means delete notifications are enabled. Windows should manage SSD optimisation automatically.

If BitLocker was only suspended, resume it:

Resume-BitLocker -MountPoint 'C:'

If the disk was decrypted, re-enable encryption through Windows Settings or the organisation's management policy and confirm that the new recovery material is escrowed correctly.

If C: did not expand on a larger SSD

Check the layout in Disk Management. Windows can extend C: only into unallocated space immediately to its right. If Windows RE sits between C: and the unused space, Resize-Partition cannot jump over it.

Options are:

• restore again with correctly planned partition sizes;
• use a trusted offline partition editor to move the recovery partition after creating an image;
• deliberately disable and recreate WinRE at the end of the disk, following Microsoft's layout guidance;
• create a separate data partition in the unused space.

Do not delete the recovery partition solely to make the disk diagram look tidy.

When unallocated space is adjacent to C:, preview the supported maximum and extend:

$size = Get-PartitionSupportedSize -DriveLetter C
$size | Select-Object SizeMin, SizeMax
Resize-Partition -DriveLetter C -Size $size.SizeMax -WhatIf

Remove -WhatIf only after verifying the selected volume and backup.

If the cloned disk does not boot

Begin with the low-risk checks:

1. disconnect the old disk and unnecessary USB storage;
2. confirm the new SSD appears in UEFI firmware;
3. confirm firmware is in UEFI mode, not legacy/CSM;
4. select Windows Boot Manager for the new disk;
5. boot current Windows 11 installation media and choose Repair your computer → Troubleshoot → Startup Repair.

If Startup Repair fails, open Command Prompt from Windows setup. Drive letters can change in recovery, so identify Windows and the FAT32 EFI volume rather than assuming:

diskpart
list disk
list volume
exit

dir C:\Windows
dir D:\Windows

Find the volume that contains the real Windows directory. Return to DiskPart, select the small FAT32 EFI volume and temporarily assign it S::

diskpart
select volume <EFI volume number>
assign letter=S
exit

Then recreate UEFI boot files, substituting the correct Windows letter discovered above:

bcdboot D:\Windows /s S: /f UEFI

Microsoft documents bcdboot as the tool for setting up or repairing the boot environment on the system partition. A successful message is encouraging; restart with the USB removed and confirm the firmware boot entry.

If the SSD is absent from Windows setup but visible in firmware, the machine may use Intel VMD, RAID or another storage controller requiring a driver. Obtain the correct storage driver from the computer manufacturer or use a current recovery image. Do not casually change RAID/VMD to AHCI: Windows may become unbootable unless the driver and boot configuration are prepared first.

If Windows boots only while the old disk is connected

The new disk probably lacks a working ESP or firmware entry. Shut down, disconnect the old disk, boot Windows installation media and repair the new ESP with Startup Repair or bcdboot. Do not accept a two-disk arrangement unless it is intentional and documented.

If Windows RE is disabled after cloning

Check:

reagentc /info

If the recovery image and partition were cloned correctly, re-register them:

reagentc /disable
reagentc /enable
reagentc /info

If enabling fails, verify that the recovery partition exists, has adequate free space and contains a valid winre.wim. Do not download a recovery image from an unofficial site.

Legacy MBR source

Windows 11 normally boots using UEFI, Secure Boot-capable firmware and GPT. If the source is unexpectedly MBR, do not combine conversion, shrinking, cloning and firmware changes in one untested leap.

Microsoft supplies mbr2gpt.exe. Validate first:

mbr2gpt /validate /disk:0 /allowFullOS

Only after a successful validation, independent backup and recovery plan should an administrator consider:

mbr2gpt /convert /disk:0 /allowFullOS

The conversion creates an ESP, installs UEFI boot files and changes the partition table. Firmware must then boot in UEFI mode. Read Microsoft's current MBR2GPT limitations before using it; a failed or unsupported layout needs manual work.

Common mistakes

• Choosing disks by Disk 0 and Disk 1 instead of verifying model, serial and capacity.
• Assuming two products labelled 500 GB have identical sector counts.
• Thinking BitLocker suspension decrypts the volume.
• Using -icds because Clonezilla said “too small” without calculating partition boundaries.
• Copying only C: and forgetting the EFI and recovery partitions.
• Booting the first clone with the old disk still attached and never proving independence.
• Letting both source and destination remain writable before the clone is validated.
• Expanding C: until no space remains for WinRE or ordinary Windows updates.
• Publishing the backend drive through a cheap USB bridge that disconnects under sustained load.
• Treating a successful boot as proof that files, recovery, BitLocker and backups work.
• Erasing the old disk immediately.

Practical decision table

Completion checklist

• Independent file backup exists and has been opened successfully.
• Source and destination model, serial and capacity are recorded.
• Recovery key is stored outside the source disk.
• Windows installation or recovery USB boots on this computer.
• Source file system and disk health are acceptable.
• EFI, MSR, Windows, WinRE and OEM partitions are identified.
• Smaller-target calculation includes actual GiB capacity and the last partition boundary.
• BitLocker is deliberately suspended or decrypted according to the selected tool.
• USB ISO came from the official site and its hash was checked.
• The clone or image completed without errors.
• First boot succeeded with the source disconnected.
• Windows Update, applications, files and another restart were tested.
• Windows RE and BitLocker are enabled and verified.
• The new disk is covered by a working backup job.
• The old disk remains untouched until the validation period ends.

Frequently asked questions

Can I clone a 1 TB disk to a 500 GB SSD?

Yes, if every required partition can be resized and placed within the destination and the used data leaves adequate headroom. Shrink C: first, move or recreate any partition whose end lies beyond the target, and remember that encrypted or unsupported file systems may force sector copying. “Only 200 GB used” is necessary information, not a complete proof.

What is the absolute minimum size for C:?

Microsoft's deployment documentation lists a 20 GB Windows-partition floor for 64-bit Windows and Windows 11 requires a storage device of at least 64 GB, but neither figure describes a comfortable, updated workstation. Treat 100 GB as a constrained practical floor and 150–250 GB as a more sensible starting range for ordinary use, then adjust for applications, profiles and update retention.

Should I copy the recovery partition?

Usually yes. It contains Windows RE and supports startup repair, reset and BitLocker recovery workflows. Aim for a 1–2 GB recovery partition with useful free space on a newly planned layout.

Is Rescuezilla better than Clonezilla?

Rescuezilla is friendlier and better for an occasional graphical workflow. Clonezilla exposes more expert controls and is popular for repeatable technician work. Both can destroy the selected destination; the user interface does not replace disk identification.

Can I clone while Windows is running?

Windows-native tools can use snapshots for a hot clone, but offline cloning reduces changes during the copy and avoids some locked-file and boot-partition complications. For an operating-system migration, schedule downtime when possible.

Will Windows activation survive an SSD replacement?

Normally an SSD change on the same computer does not invalidate a digital Windows licence. A clone moved to substantially different hardware may require reactivation and new drivers, and OEM licensing terms may limit transfer.

Does an NVMe clone require special alignment?

Modern Windows partitions normally use 1 MiB alignment, which is suitable for 4K storage. Use the cloning tool's recommended SSD or 1 MiB alignment. Do not preserve an old cylinder-aligned Windows XP layout merely for nostalgia.

Related reading

• LINUX IS NOT SECURE! A practical server-hardening manual
• Nmap: defensive discovery with written scope
• You ran the mystery script. Assume it won.

References

• Microsoft: UEFI/GPT-based hard drive partitions
• Microsoft: Windows 11 requirements
• Microsoft: Windows RE partition requirements
• Microsoft: MBR2GPT
• Microsoft: Suspend-BitLocker
• Microsoft: BCDBoot
• Microsoft: create Windows installation media
• Microsoft: Recovery Drive
• Rescuezilla help and smaller-disk limitation
• Clonezilla disk-to-disk guide
• Clonezilla advanced restore parameters
• Rufus
• Ventoy getting started
• Hasleo Disk Clone

Safety boundary

Clone and resize only disks you own or are authorised to administer. Every destination-disk operation is destructive. Verify identifiers, keep an independent backup and recovery key, and stop when the source shows hardware failure or the target layout cannot be proven to fit.