Migrating a Bitlocker Windows installation to a larger drive

I recently cloned a Windows 10 installation's Bitlocker encrypted drive to upgrade a PC's solid state drive (SSD) from a smaller SATA drive to an NVMe drive. Here are thorough notes on what I did if you need to do the same.

The Bitlocker aspect doesn't actually seem to make much difference here. This is the same process you could to clone an unencrypted Windows disk, but it's worth noting that this does work for Bitlocker-encrypted disks.

Caveat

This upgrade ostensibly seemed to work fine.

However, with the cloned drive, the Windows Mail app required reinstallation as it wouldn't load. From reading around, there can be some weirdness around Universal Windows Platform (UWP) applications. Right now, I can't find any specific fix outside of reinstalling those affected apps. In this case, reinstalling the Mail app seemed to work, and had retained all the existing data. That aside, other UWP apps seemed to work on the machine, so I don't know. I love computers very much.

Do be prepared if you have lots of UWP apps: you might still need to reinstall them though. I couldn't find any other workaround, but only looked for a few minutes.

Upgrade process

For this kind of installation, I typically write out step-by-step what I intend to do first, so I'm less likely to miss a step or forget something. Ultimately, the process as it turned out didn't differ that much from what I sketched out at first.

Of course, there was one issue I didn't anticipate: there was a Windows recovery partition at the end of the original drive. This meant that the free space after upgrading was not contiguous with the existing Windows volume: the recovery partition was in the way, preventing the volume from expanding to fill the drive. To fix this, I had to move the Windows recovery partition to the end of the newer, larger drive, so that the existing Bitlocker volume could be expanded by the Windows Disk Management tool. This Super User question helped solve that problem, and this answer is used as the basis for some of this guide.

Below are my corrected notes after completing the upgrade, broken into four sections. It's worth reading through the whole set of instructions first. These aren't completely exhaustive, but should be enough to get you to what you need.

Preparation

  1. Backup the old drive entirely first, before starting the upgrade. The likelihood of disaster may be small, but the impact of that is high if you have no backup. So, backup.
  2. Ensure you have the Bitlocker recovery key and it works. I don't think you should need the recovery key for upgrading a drive in the same PC, but, again, best to check this before you start.
  3. Shutdown the PC, entirely powering it off. (I actually forgot to do this and hibernated, but this was also fine, provided the PC is powered off.)
  4. Open up the PC, install the new drive into the expansion slot inside the PC and close up the PC again.
  5. Update drive firmware if there is a update needed. You can try searching the manufacturer's site to see if an upgrade is available. Manufacturers don't always make this information easy to discover. You may just want to install whatever utility the manufacturer offers to check for firmware updates and update via that. (Most manufacturers have some kind of tool; a few provide updates via a bootable disk image.)
  6. Download a bootable Linux installation: Ubuntu works fine and has all the tools you need.
  7. (Optional) Verify the download; there is a guide for checking Ubuntu downloads.
  8. Write that Linux image to a USB drive or DVD as a "live installation.
  9. (Optional) Verify that the Linux image has been written correctly: you can do this easily if you're already running Linux.

Cloning the disk

  1. Boot the live Ubuntu installation from a USB or DVD. You'll probably need to enter the boot menu of your BIOS to select the USB or DVD to boot from. For Ubuntu booting via a DVD, you may want to add the custom boot parameter: fsck.mode=skip to skip the integrity check as it is often very slow via DVD.
  2. (Optional) Wipe the newly installed drive. This may not be strictly be necessary if a new drive, but I tend to do this anyway. The Arch Linux wiki has lots of information on using the hdparm (for SATA drives) and nvme-cli (for NVMe drives) tools to do this. In the current Ubuntu release (22.04.1), the nvme-cli tool is not installed, so you'll need to open a terminal and install it via sudo apt update && sudo apt install nvme-cli. You will run these commands in a terminal.

  3. Run some command to clone the drive. I went with running in a terminal: sudo dd if=/dev/old-drive-device-name of=/dev/new-drive-device-name status=progress bs=32M; sync

    Use the lsblk command to find the correct old-drive-device-name and new-drive-device-name. Triple check that you have the input (if) and output (of) files the correct way round before running the command.

    The bs controls the block size. The default block size is small, so we specify a larger one to speed up cloning the disk: the transfer rate was about 500 MB/s transfer rate, probably limited by the read speed of the SATA SSD drive.

    The final sync is to ensure anything cached is written to the disk, although shutting Linux down via the shutdown option (as opposed to just powering off) as we'll do next should also ensure this.

  4. Shutdown Ubuntu entirely. Left click the mouse in the top-right of the screen where the volume icon is, and you'll see the power options.

Reorganising the disk volumes

  1. Check the boot order in the BIOS and reorder it if necessary to prioritise the new drive over the old.
  2. Boot into Windows.
  3. In an command prompt as administrator, use Windows' REAgentC command to disable the Windows Recovery Environment temporarily: reagentc /disable — you could optimise this and save a reboot by doing this in Windows before cloning.
  4. Shutdown Windows.
  5. Boot back into your Ubuntu live installation once again.
  6. Run the GParted graphical application. Move the Windows recovery partition to end of drive. You'll be prompted to fix the incorrect GPT record, which will be wrong due to the change in drive size. You need to do this otherwise moving the partition will fail. Apply the partition changes, which should now be successful.
  7. Shutdown Ubuntu again.
  8. Boot back into Windows.
  9. In an command prompt as administrator, run reagentc /enable to enable the Windows Recovery Environment again.
  10. Run the Computer Management application as administrator, and go to Disk Management.
  11. Right click on the Bitlocker Windows volume, and select "Extend Volume" to fill the unused space.
  12. Check the properties of the newly expanded drive in Windows Explorer and confirm that the drive has a larger size.

Final checks and cleaning up

  1. Boot into the Windows Recovery Environment to confirm that it works. It's also possible to boot to this directly with ReAgentC via reagentc /boottore command.
  2. After you have checked the Windows recovery environment, reboot back into Windows.
  3. Via the Activation settings, check that Windows is still activated if it was activated previously. I didn't need to reactivate the PC in this case.
  4. Shutdown Windows.
  5. Open the PC, disconnect the old drive, and then remove the old drive from the PC.