What's causing xcopy to tell me Access Denied?

Question

The postbuild task for one of our solutions uses xcopy to move files into a common directory for build artifacts. For some reason, on my computer (and on a VM I tested), the xcopy fails with "Access Denied". Here's what I've done to try and isolate the problems:

• I tried a normal copy; this works.
• I double-checked that none of the files in question were read-only.
• I checked the permissions on both the source and destination folder; I have full control of both.
• I tried calling the xcopy from the command line in case the VS build process had locked the file.
• I used Unlocker and Process Explorer to determine there were no locks on the source file.

What have I missed, other than paranoid conspiracy theories involving computers out to get me? This happens on my dev machine and a clean VM, but doesn't happen for anyone else on the project.

Answer 1

Usually this happens because there's another process locking the file. I bet your machine has a different number of cores/different speed than the others. Try inserting some sleeps to see if it solves the problem.

Answer 2

Try Filemon and see if it turns up any more detailed information.

Answer 3

Problem solved; there's two pieces to the puzzle.

The /O switch requires elevation on Vista. Also, I noticed that xcopy is deprecated in Vista in favor of robocopy. Now I'm talking with our build engineers about this.