The Windows Backup and Restore feature allows you to save files and system images to external backup devices such as hard drives and flash drives. However, backing up files become problematic if the directory your backing up files from isn't configured properly, or if you're having issues with the devices you're backing files to. There are ways to solve or work around backup problems quickly and safely. Hard Drive
b> A backup will not complete if the files you're backing up exceed the amount of space left on the external hard drive. If you're backing up large system files, Microsoft recommends saving the backup to an external hard drive that can hold at least 200 GB. If you're running out of space, you must delete content to create space for others or use another hard drive. Error Codes
In some cases, Windows displays the following error codes when it's unable to complete a backup: "0x80070001 (Invalid Function)" or "0x81000037: Windows Backup failed while trying to read from the shadow copy on one of the volumes being backed up." These error messages usually appear if Windows is unable to backup a specific library or if you opt out of adjusting your backup settings and settle for the default settings in the Windows Backup and Restore Feature. Reparse Point
b> If you're unable to backup a specific library and run into error code messages, removing the reparse point allows you to complete the backup. A reparse point is a file that contains information about the user on a computer. If it doesn't point to a location that contains some of the data you want to backup, error messages appear when you try to back up your files. Type "CMD" in the Start Search box to open the Command Prompt. In the Command Prompt, typing "DIR /AL /S" and pressing Enter lists the reparse points. Each entry says "JUNCTION," which also means reparse point. The entries also tell you the location of the reparse points in Windows Explorer. If you locate a specific reparse point in Windows Explorer, delete its mounted volume from the device's Properties. Once deleted, you should be able to back up your files. Discs
b> If you're backing up files to a disc, you'll run into problems if the discs are non-rewritable and already contain data, or if they are severely scratched or damaged. Non-rewritable discs can only be used once, while rewritable discs can be used to read and write data several times. If the CD or DVD you're using is severely scratched, the optical disc drive spins harder than usual in an attempt to read it. If it's incapable of reading the disc, the backup feature may freeze or display an error.
Windows backup or restore errors 0x80070001, 0x81000037, or 0x80070003 http://support.microsoft.com/kb/973455 - workaroundissue12