Windows 7: Windows Backup failed 0x81000031

Question

Windows backup ran, and my once-pristine and empty backup drive now has something filling its space, so I assume some files were successfully backed up. Thing is, the Action Center icon has the red x on it and it comes up with one issue: Check, your backup (Important). Clicking this issue produces the following dialog:
Windows Backup: Troubleshooting Options
Check your backup
Windows Backup failed while determining libraries location of one of the users included in the 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.
Options:
*Try to run backup again
*Change backup settings
Error code: 0x81000031
Thing is, I'm using home premium. I don't see bitlocker as an option and I'm not terribly enthused about having to repair bitlocker when I can't use it to begin with. (Primarily, because I use Windows 7 Home Premium. Even if I used a version which supported bit locker, I'd never use it to begin with - I lack a TPM chip which means that anybody who has physical access to my machine could compromise my security regardless of bitlocker, it'd just take slightly longer for them if bitlocker were present.)
I'm digressing, the point is I don't use bitlocker and I don't know how not having bitlocker prevents Windows 7 from copying files from one drive to another and making a note in a logfile that the files were backed up. I realize I simplify the method of backing files up but it doesn't get much more complex than copying them to a separate location and timestamping them.
tl;dr: Windows Backup produced error code 0x81000031 because bitlocker drive encryption cannot be used. I don't want to use bit locker drive encryption I just want to back my files up to an external drive. Suggestions? Preferably ones that don't make me run Windows Startup Repair.

Answer 1

Well 4 years later same problem simple fix, did every thing else as suggested by microsoft sys repair start up repair etc etc and just removing the drive that was included in library fixed the issue i have spent hours on
now have to reinstall all that sys restore removed...SO EVERYBODY do what Sneha said first..
Clicked "Start", then "Computer".
Right clicked on the "Library" I wanted to modify, and selected "properties".
Immediately saw that my DVD drive was an included folder in the library.
Clicked on the drive in the list, and the Remove Button became active.
Clicked on "Remove" and it removed the drive from the list.
Clicked on "Incude Folder" and added in my real backup folder location (not required, I just want a libray connection to
it).
Clicked on "Ok".   thanks ath1234 for the process..Cheers