This question already has an answer here:
Alright. I'm trying to move my games (from one drive to another), but as you know there is close to no possible way to do so.. Without redownloading it. No thanks to the recent client updates, simply copying the files over (and uninstalling the old location) does not help at all.
So: Is there any way to get Steam to redownload, and then instantly make it complete (then copy the files over)? (That means not redownloading the game again. Instead, it downloads nothing and the game is marked as downloaded.. But no actual files are downloaded. Instead, the source is the game files, untouched, and NOT in as a "backup1")
1 Backup = .csd, .csm and .sku files in the [Game Name]\Disk_[# No.][ID]depotcache[# Num].csm etc. format and file structure.
Question: How do you trick Steam into starting a download, and then "instantly" finish it without downloading a thing? As the solution in this post does not work. Or it may be because I'm on a beta build.