I was working with a user who uses Windows Fax and Scan to scan documents. One day it stopped scanning and threw an error that read, "A problem prevented the document from being scanned. Please try again or see Help and Support or the information that came with the scanner."
All research pointed to running the application as an administrator. Tested running as admin and we were able to scan. We then tried running normally again and the error occurred. Running as an admin was not a viable solution, but as a temporary fix, I created an alternate local admin account and a runas shortcut to run the application with while I searched for a true solution.
I found one article that caught my eye, because it referred to issues saving scans as .tiff format, which this user was trying to do. Turns out that when Windows Fax and Scan saves as .tiff, it creates a temporary version of the file and saves it in C:\users\%username%\app data\local\Temp. Once the magic number of 10,000 files is reached, it will no longer accept new temp files. When you run it as an admin since that is technically saving to the admin's temp directory it appears to work magically. I checked the user's temp files and sure enough there were 10,001 .tiff files. Deleted them all, tested scanning again and it scanned without issues.