An important note when using any backup software to image your drive. I recently went to update my system image files using an external USB HD. AOMEI Backupper couldn't find the backup file, though I found the file myself just where it was originally saved. After a little trouble shooting, I discovered the issue.
Windows will by default assign a random drive letter when plugging in an external USB drive. The problem stemmed from the fact that the original backup image file was saved to a path using the drive letter J:. But my WIN 7 desktop now assigned the drive letter as H:.
This was easily solved by going into Windows Disk Management, and forcing the drive letter J: to be assigned to my external HD. But points to a potential glitch in backup software, many of which do not have a provision to specify the location of the backup image files. And behooves the point not to change the path of the backup file. Either the drive letter, folder, or file name when you make an image file. Your backup software may not be able to find the file to either update or restore your system. Check your particular software.
This may also be an issue with NAS storage used for backup if a different IP location is assigned.
On another note, I have been exceptionally pleased with the open source and fast FreeFileSync app that I now use for automated daily backups of my personal encrypted data files, including both my Firefox and Thunderbird profiles. And also to auto backup My Documents folder multiple times a day. Though can even be set to auto backup key folders soon after it detects any changes.
However, FreeFileSync may not be as user friendly to everyone, as you must create a batch file for automated backups. Then link to it by creating a backup job using Windows Task Scheduler. Not particularly difficult. And makes auto backups seamlessly in the background. Note that you don't need to have FreeFileSync running as Windows Task Scheduler will open the application, run the batch file, and close the application.
Best part is that FreeFileSync is completely FREE.