I had a workunit that I had crunched for quite a long time. It exited and now shows in my results as client error exited on sept 15. Now the WU folder on my hd is still there taking up 300MB. Is it safe to delete this? I have completed another WU succesfully and realize that I must keep the zip files it creates for future use. However this failed WU has no zip files in the dir since it exited early with errors. Any info would be greatly appreciated.

Yes, you can delete the folder for failed WUs.