BitLocker Setup could not find a target system drive to prepare
There are two scenarios that can cause this error, says Microsoft.
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 filesHibernation files (Hiberfil.sys)Windows Registry filesNTFS 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
2] Shrink Drive size
Open Command Prompt (Administrator) and execute the following command: 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: To know more about disabling the Microsoft BitLocker Administration and Monitoring (MBAM) GPO, please check the reference at docs.microsoft.com. 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.
