Backup did not complete successfully--Error code 0x81000037

Hi landina,

1.   Do get us the exact error.

2.   What steps were followed to eliminate0x80070002?

Step 1:

Did you refer the steps mentioned in the below article?

http://support.microsoft.com/kb/951002

If you have not tried these, I suggest you to give it a shot.

Step 2:

This issue may occur if there are duplicate accounts on the computer.

Important:  This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:

How to back up and restore the registry in Windows: http://support.microsoft.com/kb/322756
 
Steps to delete the duplicate account

a. Click the Start button, type “regedit” (without quotation marks) in the Search box and press Enter.
b. Navigate to the following registry key by expanding the "+" beside the registry tree in the left pane:

HKEY_LOCAL_MACHINE/Software/Microsoft/Windows NT/CurrentVersion/ProfileList

c. Delete the duplicate profile list keys there.
d. Exit the registry editor and reboot the computer to check the results.

Regards,

Savan – Microsoft Support.