This one is weird. Visual Studio 2008 seems to not be releasing its handle to the .DLLs getting created for my project, so the second time (and subsequent times) I build, when Studio attempts to overwrite the changed .dlls, it gets an access denied error. I also cannot copy/delete the .dll in question (Tasks.dll) while Visual Studio is open after I've built once. Process Explorer tells me that the file is in use by devenv.exe, so I know Visual Studio isn't letting go of it after the build finishes.
Has anyone seen this before, and if so, what can I do about it? Obviously, opening and closing visual studio between every build is not an acceptable solution, and the problem has persisted across system restarts.
Some more background: I am using the error-causing project's DLL (Tasks.dll) in a UsingTask MSBuild directive in another project, let's call it Test. Project build order is set so that Tasks is built before Test, and then Test's AfterBuild task calls a task from /bin/debug/Tasks.dll.