What were you using for your "file backup with a backup image"? Backup & Restore with a system image included? If so, you need to be aware that Microsoft
deprecated this feature more than two years ago in Windows 8 and 10 meaning that any further development ceased (including for W7) advising that
"We recommend that users use full-disk backup solutions from other vendors."
My personal experience with Backup & Restore's system imaging is that it can be temperamental, failing to recognise an image that could be restored just when you need it the most. Also, the file backup part of the operation creates a series of multiple zip files, making it virtually impossible to retrieve a file unless you have a functional Backup & restore on your system.
Having said that, your 13 hours does sound excessive. How far had it got? Was it still backing up files, or had it started on the system image? 450GB used is quite large, the Windows system itself would only account for some 20-30GB of that. If the bulk of the remainder is accounted for by your user files you may find the 500GB external HDD is too small to hold a system image as well as the files backup. Your backup may have stalled due to lack of space on the destination drive.
Personally I'd recommend using
Macrium Reflect Free to make a system image. Not only is it more reliable than Backup & Restore, but a Macrium system image can be mounted as a virtual drive so that you can retrieve individual files, you'd no longer need a separate files backup.
