Steam just erased all my games without warning. Here's my setup and what I've done recently that could be related (I'm including probably too much detail in the hopes it helps someone figure out what happened):

  • I've had my Steam account in use on 3 computers for months, and added a fourth about a month ago. There were no issues with this other than the normal needing to coordinate which one is signed in at what time.

  • Yesterday I restored part of a backup (made on Computer A several months ago) to Computer B. This was a bit problematic; it failed once, then again when I tried in Offline Mode, and worked the third time although there were connection issues and I had trouble getting Steam to exit after it finished. In the end this exercise was entirely useless since Steam wanted to download the entire games again anyways.1

  • Today I completed some of the downloads on Computer B (COD1 and Worms Crazy Golf).

  • I then signed in on Computer C, forcing Computer B to be logged out.

  • Then I put Steam into Offline Mode on Computer C, and logged in on Computer B again.

  • Next I started up Worms Crazy Golf on B and exited Steam when I realized that B didn't have my saves since the game doesn't use Steam Cloud. (Despite this, Steam reported that it was syncing to Steam Cloud when I exited.)

  • Finally I started Steam on Computer A before connecting to the internet, and it naturally gave me a connection error. I connected and hit Retry. Instead of logging in it said something like "Exiting", the main window flashed briefly, and it exited.

  • I believe this is the point where it erased everything because the log-in window came back up about thirty seconds later and, while it remembered my username, it didn't remember my password and otherwise looked like it does when you start it up the very first time.

  • After signing in none of my games were marked as installed, and my Favorites menu was empty (and ended up empty on the other PCs as well). My steamapps\common folder on the hard drive was empty and nothing could be recovered with undelete tools.

So, now I have a few questions:

  • Why did Steam erase everything? Is this a known issue?
  • Did I do something "wrong"? I was the one doing all of the actions, setting up and playing, though who knows what their heuristics thought of it. My account doesn't appear to have been suspended or anything.
  • How can I prevent this from happening again?

1The re-downloading could be because there were updates to the games, but I don't think so since the downloads were the size of the entire games. COD:MW2 couldn't possibly have had 11 GB of updates, right? Either way I am sticking to manual backups from now on, Steam's are too slow and obviously unreliable.

  • Anything else that can have caused this issue? I don't believe the Steam client itself did this.
    – mordi2k
    Commented Dec 11, 2011 at 3:30
  • @mordi2k Nothing else was affected, so I think it's logical to assume it was the client. I'm not having any other problems with my computer. Commented Dec 11, 2011 at 3:35
  • Check to make sure you don't have two different Steam install directories (such as one in Program Files, another in Program Files (x86), or on another hard drive). If Steam somehow reinstalled itself to a different directory, it would explain your problem, as the games aren't really missing, it's just that Steam is looking in the wrong place for them.
    – Sterno
    Commented Dec 18, 2011 at 23:01
  • @Sterno Thanks for the idea, but it looks like only the default PFx86 folder exists/is used. Commented Dec 18, 2011 at 23:45
  • you said up top that computer A had an old back up; did you restore the old backup to A instead?
    – nhutto
    Commented Dec 21, 2011 at 22:37

2 Answers 2


I know of only one way that this can happen in windows, and has nothing to do with Steam other than their not-so-great decision to install all content into Program Files.

If you are on Windows 7 or Windows Vista, and you have UAC set to ON, then change it later to OFF, this can happen.

UAC does thing evil thing where if a program tries to write to a "protected" area like Program Files, EVEN IF YOU ARE ADMINISTRATOR, when you get a UAC prompt and give permission, it actually writes any files that would normally go into that directory into a "virtualized" directory somewhere else.

If you turn off UAC, that will no longer happen, and as an awesome bonus, it will no longer know about the files that it virtualized.

So in your case, if you had UAC on, installed a ton of games, then later got sick of UAC and turned it off, this would happen as you described.

See the second paragraph in "Features" in the article on User Account Control.

If you have done this and turn on UAC again, your content will come back, but be a TOTAL mess because if you've downloaded more stuff with UAC off, then that will be invisible when you turn UAC on, and vice versa.

this drove me a little crazy once before I realized what was happening.

i'm curious to know if this is your issue.

  • 2
    I've always had UAC off. Interesting though, thanks anyways. Commented Dec 27, 2011 at 0:49
  • The Wikipedia link you provide contradicts your answer: "The redirection feature is only provided for non-elevated 32-bit applications, and only if they do not include a manifest that requests specific privileges."
    – Kevin
    Commented Feb 18, 2016 at 6:26
  • 1
    When I was a user who was an administrator, and I gave it permission via a UAC prompt, it still virtualized files. When I turned off UAC this stopped happening. I've since moved steam to another place (S:\Games\Steam) and it ceased to be an issue entirely. This is all I know. Commented Feb 18, 2016 at 7:03

Te best solution I can come around is to simply NOT let Steam install itself into Program Files, instead I install it on something like C:\Steam directly, so windows can't come around and smack me with UAC whenever i log in or out.

The real issue here is that the Steam client is very buggy on its implementation of installed content. Sometimes it just deletes the content because another account was logged in or you logged in to some other account.

I had a related thing going on.

In my house i have 2 desktops and a laptop. My desktop has always had the steam client installed and it has the guest account enabled. A week ago my brother setup a steam account, installed the client on the second desktop and I gifted L4D2 to him. When I went to work he used the guest account on my desktop to log in to his account, logging out of mine.

As soon as i came back to log in, steam had erased Fallout 3, Skyrim and Mass Effect 1 & 2 without any reason other than logout. It has happened 3 times now, so I asume it is a bug in the Steam Client.

  • I've already said I've always had UAC off. Commented Jan 5, 2012 at 17:05

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