I'm using LabVIEW 2011 SP1 f1 on Windows 7.
Create an .lvproj file with LabVIEW and build.
LabVIEW creates a file with the same name as the .lvproj file but with an extension of .lvlps. Look at that file with an editor, it looks like a .ini file. In it there will be a couple of entries named Cache_Path[Path] pointing to /c/users/usename/Local/Temp/AB_Cache_{... where the path is probably broken up with Line0001, Line002, etc entries.
Now hit clean and look at your project directories. The output of the previous build should be gone.
Look at the .lvlps file again, note the cache path directory, navigate to your temp directory and delete that directory.Now hit clean and nothing happens.
Also, with standard Windows 7 ACLs, if I log off, another users logs on, and tries to clean, that other user won't have access to my temp folder, and thus the clean won't do anything.
Another intersting side effect is that if you copy/rename the .lvproj file to use with a new project. Change the build process to build something slightly different, because of a bunch of UUIDs built into the (xml) .lvproj file, if you clean this new project you ended up cleaning the original one. I wouldn't call that a bug but it was certainly that I wasn't expecting.
The projects still build fine, as all new files are generated, but ones that are no longer used stick around in the generated project directories.
