Any chance you're using WINS? At first reading it felt like some record (other than pure DNS) might have expired, but then I got rather confused as to what you're describing. Here's what I suggest, log the error codes to your mapping attempts, this way we can get a clue as to what is happening. Also, when a problem seems intermittent, it means we're missing information, and in this case, I'm also wondering if there might be something in your cache that's changing the behaviour of your script/mappings. If you like, I've got a personal logon script that logs to Windows Event log. f.