What is going wrong when Visual Studio tells me "xcopy exited with code 4"

Question

I'm not very familiar with post-build events, so I'm a little confused as to what's going wrong with my program. When compiling in visual studio 2010, I get the following:

The command "xcopy C:\Users\Me\Path\Foo.bar\Library\dsoframer.ocx C:\Users\Me\Path\Foo.bar\bin\Debug\ /Y /E /D
xcopy C:\Users\Me\Path\Foo.bar\ApplicationFiles C:\Users\Me\Path\Foo.bar\bin\Debug\ /Y /E /D
xcopy C:\Users\Me\Path\url\ C:\Users\Me\Path\Foo.bar\bin\Debug\ /Y /E /D
rmdir /S /Q C:\Users\Me\Path\Foo.bar\bin\Debug\.gwt-tmp" exited with code 4.    

The program appears to run fine, despite this error, but I don't want to just ignore this issue and hope nothing bad happens. Strangely, this line started out as only a single command (the first xcopy) but as I continued to compile the project (fixing other problems, mostly references) the error message expanded larger and larger. Any idea what could be going on?

Edit: Here are the postbuild events that seem to be failing --

xcopy $(ProjectDir)Library\dsoframer.ocx $(TargetDir) /Y /E /D
xcopy $(ProjectDir)ApplicationFiles $(TargetDir) /Y /E /D
xcopy $(SolutionDir)com.myUrl.gwt\www $(TargetDir) /Y /E /D
rmdir /S /Q $(TargetDir).gwt-tmp

Answer 1

Xcopy exit code 4 means "Initialization error occurred. There is not enough memory or disk space, or you entered an invalid drive name or invalid syntax on the command line."

It looks like Visual Studio is supplying invalid arguments to xcopy. Check your post-build event command via Project > Right Click > Properties > Build Events > Post Build Event.

Note that if the $(ProjectDir) or similar macro terms have spaces in the resulting paths when expanded, then they will need to be wrapped in double quotes. For example:

xcopy "$(ProjectDir)Library\dsoframer.ocx" "$(TargetDir)" /Y /E /D1