disk is failing or just full? need more details...

You haven't run out of disk space? Make sure you have enough space for the entire game allocation during download/install.

If that's not the issue, stop using the drive and backup it as soon as possible. If the drive is physically damaged, read/write access will just keep adding to that. If it's quite an old drive, you want to backup your important data first.

Then run a disk check upon it.

Right-Click the Drive Letter > Properties > Tools (tab) > Error Checking > Check

If that's fine, launch Steam again and go under the top-menu Steam > Settings > Downloads (tab), then click on Clear Download Cache. This will have the download start from the beginning again, but remove any corruptions.

Did you install the bad windows update?
https://www.youtube.com/watch?v=sU_WepeHUd8

Too bad for people who cheaped out on dram.

Originally posted by Majestic Turkey:

Did you install the bad windows update?
https://www.youtube.com/watch?v=sU_WepeHUd8

Too bad for people who cheaped out on dram.

Good point about that as well.

Originally posted by Talby:

disk is failing or just full? need more details...

Disk is not full

You could test copy some large movies see if error pops up

Originally posted by HypersleepyNaputunia:

You could test copy some large movies see if error pops up

Oh yes good idea

Your Steam folder is set to Read Only.

Originally posted by Masque:

Your Steam folder is set to Read Only.

Don’t think so

Have you checked the SMART data for the drive?

https://www.howtogeek.com/134735/check-ssd-or-hdd-health-with-smart/

toss computer in trash.