I have installed the Valve version of Steam on LMDE6.
I have used Disks to automatically mount the NTFS drive I used with Windows (doesn’t hold bootloader, it is just for Steam library storage) at boot ( /media/[username]/Gaming ) and I made it the default library folder in Steam.
Running games works perfectly (actually, performance is surprisingly good), but I cannot install them due to a “disk write error”.
I looked for solutions and found this page, from which I understand that I need to change permissions to the mounting point, but when I do, using chown -R, I get a “Read-only filesystem” error for all files and folders.
I can see no options to fix this in Disks and I tried to edit fstab once, but it messed things up so badly I had to use the USB drive with the portable installer to fix things.
I am going to specify in the body of the post that this is a drive I used as library drive only for Steam, it is not the one holding the Windows boot.
Would that change things?
Knowing M$, yeah, they probably lock all the attached drives when in hybrid shutdown mode.
I’d still try either Shift+Shutdown, or as another commented suggested, just disable Fast Boot.