I've been trying to fix the inability of sfc to repair files by using DISM. I've made several attempts at running DISM all of which have failed. Here is a list of what I (can remember) I've tried.
DISM /Online /Cleanup-Image /RestoreHealth
I also updated a Group Policy and then tried the above command as well. Group Policy was Computer Configuration > Administrative Templates > System > Specify settings for optional component installation and component repair. I Enabled the setting and then marked the Contact Windows Updated directly [...] checkbox.
I also tried the steps posted here.
I then downloaded the eval ISO for Windows 8.1 Enterprise 64-bit (matches my OS) and tried running:
DISM /Online /Cleanup-Image /RestoreHealth /Source:WIM:c:\Users\<username>\Downloads\win8.ISO:\Sources\install.wim:1 /LimitAccess
At this point I am in trial and error mode so I mounted the ISO and tried
DISM /Online /Cleanup-Image /RestoreHealth /Source:WIM:D:\sources\install.wim:1 /LimitAccess
DISM /Online /Cleanup-Image /RestoreHealth /Source:D:\ /LimitAccess
I have also run DISM with /CheckHealth and /ScanHealth, both indicated the store was repairable.