Mapped drives on VPN disconnect and only reconnect after reboot

Solution 1:

This is most likely an issue with the desktops. By default, the "keep alive" function of the Windows network drive mapper is 15 minutes. You can find more details and steps to resolve the issue here. You could try to fix this from the server end, by extending or eliminating the auto-disconnect option.

In short, on the server end, from a command prompt, try:

net config server /autodisconnect:-1

You may need to edit the registry for the desktops having this problem as well:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Service\lanmanworkstation\parameters
Value: KeepConn
Data type : REG_DWORD
Range : 1 to 65535 (sec)
Default value: 600 sec = 10 mins

Note: you can't make it an infinite number. I would recommend using 8 hours, since that's one business day; then have people reboot in the morning to start over.

Final Note: I wouldn't rule out that those desktops might also be experiencing packet drops or network lag, which would disconnect the drives if the drives couldn't connect to to the server.