

A pop-up will appear warning that this will delete all files and the game will have to be re-installed. In the dropdown, click "Delete local files.". THis is a guess, so its up to you if you want to try.
Since you have bought the DLCs, they will be downloaded at the same time. THis may not be the most elegant fix, but try deleting your content and then re-downloading Space Hulk.

If all is well, the next time you launch your game you will briefly see an “Access the Steam Community while playing. If you move the Steam application the pointer to the Steam application is updated. It appears that after the first launch the Steam games now “know” where the Steam application is located. Solution: The Steam application has to be in the same directory as the Steam games the first time that the Steam Overlay is launched. "Enable Steam Community In-Game" checked in the Properties dialog box accessed by right-clicking the game title in the Steam Library. "Enable access for assistive devices" checked in System Preferences > Universal Access control panel. Settings: I have a Macintosh Mac Pro running OS X 10.6.7. When I press “Shift+Tab”, the on-screen results are the same as if I had just pressed the “Tab” key. Store." I also can’t open the Steam Overlay in any Steam game when I press “Shift+Tab”. When I try to access the store, an error message dialog box pops up that states “You must enable the Steam Community In-Game and restart TF2 to use the Mann Co. Problem / Issue: I am unable to access the Team Fortress 2 In-Game Store. If you are a GoogleBot, or having trouble falling asleep, read on. Go buy yourself a spiffy new hat to celebrate. So if you had the same problem as me, move your Steam app. In appreciation of everyone’s help and to assist other people into Googling their way to this thread, I’m summarizing the problem/solution and how to get the information that a Valve representative will need to start troubleshooting similar Steam Overlay issues. I’d also like to thank Synta圎rror for volunteering some Terminal app-free ways of getting to some essential information. Special thanks go to JoeR Valve for reaching out via this forum and providing quick, detailed, and personable technical support. Problem solved! The Steam application had to be in the same folder as the Steam games. I found this in another forum, seems to be related to the issue: It's really hard for me to come up with a fix for something that doesn't show up as an error straight away.But I can't talk to the coders as they are all on holidays until the 6th.
