BitLocker Setup could not find a target system drive to prepare

If you receive BitLocker Setup could not find a target system drive to prepare, You may need to manually prepare your drive for BitLocker message while using the BitLocker Drive Encryption Tool on Windows 10 then this post may be able to help you.

BitLocker Setup could not find a target system drive to prepare

BitLocker Setup could not find a target system drive to prepare

There are two scenarios that can cause this error, says Microsoft.

  1. You do not have sufficient free disk space
  2. The partition contains files that cannot be moved.

You do not have sufficient free disk space

For the setup to find that target system drive, at least 10 percent of the active partition must remain free after the partition size is reduced.

To resolve this error, you may run Disk Cleanup Tool, disable Hibernation to delete the large hiberfil.sys file and move files to another partition or an external drive.

The partition contains files that cannot be moved

The BitLocker Drive Preparation Tool may resize partitions to prepare a hard disk for BitLocker. As such, some unmovable files like the following may prevent the tool from defragmenting and resizing partitions:

  • Page files
  • Hibernation files (Hiberfil.sys)
  • Windows Registry files
  • NTFS metadata files like $mftmirr, $secure, $volume, etc.

To resolve this issue, you need to do the following:

Disable Paging as well as temporarily disable hibernation, and delete the Hiberfil.sys file and the Pagefile.sys file. Run the command powercfg -h off in an elevated Command Prompt. It will disable the hibernation mode. To disable the Paging file. Under the Virtual Memory settings. Type “performance” in the search bar and open the option for “Adjust appearance and performance for Windows.” Under the Advanced tab, click on “Change” in the Virtual Memory section. Uncheck “Automatically manage paging file size for all drives.” Select the radio button at “No paging file” and click on Set. Then on OK.

Restart the computer and run the BitLocker Drive Preparation Tool again.

If these steps don’t help, you could proceed to the following.

Technet suggests you ensure that TPM is active and shrink the drive, as follows:

1] Check if TPM is active in BIOS settings

  1. Restart the computer and the second it turns ON, keep pressing the F10 key (This key might vary with the brand of the system).
  2. Navigate to TPM security (It again varies with the brand of the system).
  3. Verify that the status is ON and Active.

2] Shrink Drive size

Open Command Prompt (Administrator) and execute the following command:

C:\Windows\System32\BdeHdCfg.exe -target default -size 300 -quiet

Where c: is the System Drive. This will shrink the drive, create the small BitLocker partition and allow you to run the encryption.

3] Disable the GPO link that configured MBAM

Says Microsoft:

The tool is trying to write the boot files to the new system drive, but you might have applied an MBAM policy to prevent write-access to unecnrypted datadrives. With the data drives being unencrypted the system volume will be created but the tool will tell you that the drive is write protected This is due to the write-access prevention policy you created earlier for MBAM.

To know more about disabling the Microsoft BitLocker Administration and Monitoring (MBAM) GPO, please check the reference at

Once you have run the tool successfully, you can relink the MBAM GPO by force-updating the Group Policy by running gpupdate /force.

Related read: BitLocker Setup failed to export the BCD (Boot Configuration Data) store.

Posted by on , in Category Windows with Tags
Anand Khanse is the Admin of, a 10-year Microsoft MVP Awardee in Windows (2006-16) & a Windows Insider MVP. Please read the entire post & the comments first, create a System Restore Point before making any changes to your system & be careful about any 3rd-party offers while installing freeware.

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