Our network has Windows Server 2003 (not R2) and Windows Server 2008 R2 domain controllers at this time. We have our home directories mapped to domain DFS shares from a 2003 machine (redundant root on the other 2003 machine, the real share is not redundant and is on one of the DCs).
Originally, when it was 2003 DCs and XP clients, everything was fine. When we started implementing Vista, I believe, and for sure Windows 7, from beta to current, we started to see occasional delays accessing the user's mapped home drives, which in turn causes application launches from Explorer (including Notepad, IE, Command Prompt, etc. etc.) to be delayed. Eventually, the access to the mapped home drive times out, and all of the requested launches occur at once. If it's a set of Command Prompts, then we can see that the first prompt eventually launches in C:\Windows\System32 and the others then come up all at the same time immediately after sitting at U:\ (the home drive).
We have not been successful capturing this in Network Monitor, but we did manage to have it happen once with a launched Command Prompt trying to change to U: from C: - when that happened, we received a "Semaphore Timeout Expired" error after a delay (timeout obviously), and then the next request to change active drive letters worked.
Has anyone seen this before or does anyone have a suggestion?