My client has a server 2008R2 server and about a dozen workstations. A couple of months ago they started getting messages saying that one or another mapped drives had been disconnected. Clicking on the drive in explorer does not reconnect it but rebooting will and it will generally stay connected the rest of the day. I have changed the network connection time out settings in the registry on both the server and the workstations. This has seemed to work on a couple of the workstations but the same changes have had no effect on others. The users get their mapped drives from a login script and I have reviewed this script and find nothing unusual. I added the /persistent tag to the mapping lines just in case but that also had no effect. I don't know of any changes made to the system just before this started happening other than possibly regular monthly updates. The issue seems to be somewhat random in that it doesn't always happen every day to the same PC or at the same time. I did have one PC however that seemed to do it about 9am every morning. A search of the logs did not reveal anything happening at that time.