Win7-64 client computers connecting to a NAS share randomly get denied access. This appears as a dialog box appears saying "\\myServer\MyShare02 not accessible...you might not have permission to use this network resource..." or a dialog repeatedly asking for a password. A re-boot fixes the problem.
While the problem exists, other shares, say \\myServer\MyShare01, ARE accessible and other computers CAN access the shares denying access. So the problem seems to be on the client side.
Connecting using the IP address instead of the server name will work too.
When the problem appears, the network seems to be ok e.g. the affected computers can access other shares on the affected server and can ping etc. 'net use' doesn't show any lingering connections. Also Other computers can access the affected shares.
The NAS server is a NetGear ReadyNas Pro. The problem might be on the NAS side such as a resource limitation but since only 2 Win7-64 PCs seem to be affected the most, the problem could be on the PC side - I'm not sure yet.
I of course searched for solutions and found several tips addressing initial connection problems (use correct workgroup name, use IP address instead of server name, remove security restrictions etc) but none of those remedies address the random nature of this problem.