getting the same problem as Nuubiew7, but linda yan's response didn't help me out with the regedit...I did not see any duplicate accounts in profiles...I saw four different profiles with different numbers...but the last profile had a huge list of numbers... there has to be another way for someone who's a little afraid to mess with the registry.

Are there any logs in C:\Windows\Logs\WindowsBackup? If so, they may give you a clue to what is happening. Also a possibility here: http://grownupgeek.com/windows-7-backup-error-0x80070002 Rich

This issue occurs if backup writers cannot find the data to copy. You may temporary disable or uninstall the anti-virus and run backup again. If the issue persists, please open Event Viewer, locate to Application and Service Logs\Microsoft\Windows\WindowsBackup\ActionCenter, try to find the backup process that cause the issue. Also, please run the following command: vssadmin list writers > %userprofile%\desktop\vsswriters.txt Then open the file vsswriters.txt from Desktop, and try to find which writer has errors. You may either paste the contents in your post.Arthur Xie - MSFT