Hi,
Try to check for the behavior by following these steps:
1. You might try turning off your anti-virus and malware protection temporarily while performing the backup.
2. You can also try turning off the User Account Control while backing up.
3. You need to make sure that there is atleast a minimum of 400MB of free space available.
Refer: http://windows.microsoft.com/en-US/windows7/Turn-User-Account-Control-on-or-off
Note: Ensure to enable the User Account Control and your anti-virus back on the computer after you finish these steps. It is not recommended to disable these settings on the computer. This is just to troubleshoot the issue.
Also check if to see if there are any disk errors which might be causing this issue.
Refer:http://windows.microsoft.com/en-US/windows7/Check-a-drive-for-errors
Also, place the computer in a clean boot and see if it helps.
Steps to put the computer in Clean Boot:
1. Log on to the computer by using an account that has administrator rights.
2. Click Start, type msconfig.exe in the Start Search box, and then press ENTER to start the System Configuration Utility.
If you are prompted for an administrator password or for confirmation, type your password, or click Continue.
3. On the General tab, click Selective Startup, and then click to clear the Load startup items check box. (The Use Original Boot.ini check box is unavailable.)
4. On the Services tab, click to select the Hide all Microsoft services check box, and then click Disable all.
5. Click OK, and then click Restart.
Note: Make sure you put the computer back to Normal Startup once troubleshooting is completed by following Step 7 from the following article: http://support.microsoft.com/kb/929135
Run the backup and check if this helps.
Regards,
Syed N – Microsoft Support
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