I have an application that can also run as a service via srvany. It performs a monitoring task and uses the PlaySound method defined in mmsystem.h to play a .wav notification on certain events. It runs fine under XP as an app or as a service. Under Win7, the app runs fine. But when running as a service under Win7, I get no sound. The "allow service to interact with desktop" option is available but ignored under Win7 as part of Session 0 isolation. I expect this is somehow related. I'm looking for verification or alternate approaches. Thanks.

This response has nothing to do with this thread except that I found this thread when searching for the cause of this error message. In my case, I had serialized a CStringArray object to a file using a CArchive. Somehow the file became corrupted, overwritten/filled with zeros, when my machine was shut down. When I restarted my machine and my application attempted to load this file, I got the "An invalid argument was encountered" message box. The solution was to use some easily testable numeric values that had already been written in the file prior to the CStringArray as a means to determine if the file was corrupt. At that point my logic treats a corrupt file in the same manner as a non-existent one and simply re-creates it. I've posted this here in the hope my experience might help someone else.