Well it could be MBAM PRO causing the problem i don’t know i just disabled them both to be sure. It’s on the Microsoft answer forum. Check link…
http://answers.microsoft.com/en-us/windows/forum/windows_7-system/windows-7-backup-fails-with-error-code-0x8078012d/c87171cc-dbef-45e3-bbe1-ef0d4050fe72