Fix: Steam thinks it's running in compatibility mode

When I tried to run Steam tonight on my Windows 7 Home Premium 64-bit system it said this for the first time: "Running Steam in Windows compatibility mode is not recommended. Please remove any Windows compatibility settings for all users under file properties for Steam.exe and restart Steam. Press 'Cancel' to premanently ignore this warning and continue." I found the fix below posted by ZeroHour on edugeek.net so I decided to put it here for my own convenience.

Follow the link for the original post: Post by ZeroHour

Hi Just thought I would post a solution to a problem I had with Steam on Windows 7 RC x64 (but I believe it can happen in vista as well) Everything was working in steam for weeks until I went to close it down last night, when I exited steam windows poped up with a message stating it was going to apply compatility settings to steam as it detected a problem (no cancel or way to stop it doing this)

When I relaunched steam it poped up with a message telling me: Running Steam in Windows compatibility mode is not recommended. Please remove any Windows compatibility settings for all users under file properties for Steam.exe and restart Steam. Press 'Cancel' to premanently ignore this warning and continue.

Reinstalling steam made no difference as well as trying to set compatibility settings under the shortcut. I eventually had a go of the application compatibility tool microsoft gives out to see that the settings saved on the machines local database and that triggering when I ran steam. I had a hunt through the registry and found the area where the keys are kept and deleted the key and my problems were gone.

To fix the issue:
1.Hit start->run->regedit
2.Go to key: HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers
3.Look for a entry with your path to steam.exe
4.Delete that entry
5.If you dont find it there try HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Layers

Hope this helps if you get the issue.