New
#21
See my #15
Otherwise do you have anything like Magic ISO or Power ISO installed- something that changes associations for ISOs? (Slim chance...)
Otherwise as I think I said, it's either an in-place upgrade repair install, or upgrade to the Creator's build.
Ok you could try running Dism to check for errors
DISM /Online /Cleanup-Image /StartComponentCleanup /ResetBase
If that does nothing, then a Repair Install might be your last choice, watch the video, read the tutorial This will NOT remove any personal files or programs.
Repair Install Windows 10 with an In-place Upgrade Windows 10 Installation Upgrade Tutorials
Only other thing maybe, have you changed any setting in your bios recently?? I see you have a custom built pc, so if you made any changes in your bios that might have affected your Windows. Just a long shot....
One thought- test whether mounting an iso works under a new user profile - create one for test purposes.
If so, it's very unlikely an in-place repair install or upgrade will help with this.
There's a simple answer to this:
If an Image File like an ISO, or VHD is not contiguous (i.e. in a single piece, not fragmented around the disk) it may not be able to be mounted.
If copied elsewhere there's a good chance it will be contiguous and mountable.