I'm getting this error dialog whenever I try to back up and I have no idea what to do about it:
[Window Title] Windows Backup: Troubleshooting Options
[Main Instruction] Check your backup
[Content] Windows Backup failed while determining libraries location of one of the users included in backup.
Details: BitLocker Drive Encryption cannot be used because critical BitLocker system files are missing or corrupted. Use Windows Startup Repair to restore these files to your computer.
Error code: 0x81000031
Update: I finally managed to back up some files after a long time. I'm not sure which of the following steps are necessary, but I deleted all existing back-up files, including the system image and then I unselected all the "Libraries" virtual folders and just selected my user folder under