Visual Studio Debugger Hangs

Ever since I first tried to run our software under Visual Studio 2003, I've had trouble with the debugger and the debuggee freezing solid. This problem cropped up again today in Visual Studio 2005. I knew the problem was something to do with the symbol server, but that was all I knew. Fortunately, the developer of VirtualDub has pinpointed the causes. You can find his discussion at:

http://www.virtualdub.org/blog/pivot/entry.php?id=118

The easiest solution to the second problem in the article is to "seed the cache." Visual Studio shows in its status bar (at the bottom) which DLL is being processed. In your application startup code you need to call LoadLibrary for each DLL that causes a hang, as shown in that status bar. This will force Visual Studio to download the symbols over the Internet while the process is in a "safe" state.

In my case, on a Windows Vista RTM system, I placed the following code in InitInstance() before any network calls were made:

LoadLibrary("SENSAPI.DLL");
LoadLibrary("SCHANNEL.DLL");
LoadLibrary("CREDSSP.DLL");
LoadLibrary("RASAPI32.DLL");

Note that these aren't all of the DLLs, just the DLLs at the top of the dependency hierarchy. The dependent DLLs will be loaded automatically. It's not a bad idea to just leave this code in your debug build because the problem will recur as soon as any of those DLLs are updated in a service pack. Make sure you add the related "FreeLibrary" calls if you do this.