I'm currently upgrading a Samba file server (from 3.0.23d to 3.4.3). I have a problem on the Windows client side: if the client was accessing a UNC path or mapped drive from the Samba server before the upgrade, then after the upgrade those paths or drives are not accessible.
However, I can consistently resolve the client side problem for good by rebooting the client and then re-mapping all of the mapped drives. The problem appears to be related to the client's "memory" of the pre-upgrade Samba server, which the reboot and re-map clears.
I have the same issue and same fix on Windows XP SP3 and Windows Server 2003 SP2.
This question is specifically: is it possible to reproduce the benefits of the Windows reboot without actually rebooting the client?
I have tried restarting various Windows services, disabling and enabling the network, logging out and back in again, but nothing except a reboot appears to do the trick.