On occasion, jtreg reverses a successful test result when it is unable to delete a file in the test directory. This has happened with a number of different tests and is difficult to reproduce. It is believed to be caused by the asynchronous nature of file deletion on Windows. The successful return of File.delete() only signifies that the delete is pending, not that it has completed the file deletion successfully. This can happen when another process such as a search indexer or a virus scanner holds a handle to the file pending deletion. The deletion is not completed until all such handles are released. Adding retry logic on cleanup will ameliorate this situation.