64-bit mode with Source SDK
From Valve Developer Community
(Redirected from Source SDK won't start)
The current Source SDK release has issues starting up on systems running the Source engine in 64-bit mode with the 64-bit version of Windows XP.
To correct the problem:
- In the Steam Games window, right-click on Half-Life 2 (or any installed Valve game you want to run) and select the Properties option.
- Then select Set launch options... and add the line
-32bitto the edit box. - Close the dialog and launch the game you just edited (ie. Half-Life 2). When it has successfully started up, close the game.
You should now be able to run the SDK on your 64-bit OS. Note, however, that if you run any of your Valve games without the -32bit option, your SDK will go back to being incompatible and you'll need to repeat this process.
This means that if you run a game through Hammer, you'll also need to launch that game with the -32bit command line parameter as well. The same is true running a game from a batch file, command line, etc.
