We are a small business network with ~30 XP PCs and 4 Windows 7 PCs, and I'm having network credential problems with one of the Windows 7 PCs (note: I did fresh Windows 7 installs on all 4 of those PCs, set them all up the same, and the other 3 don't have these problems). We have a SNAP network storage device that everyone's PCs access via mapped network drive. Everyone logs into their PCs using a domain account (running AD on Win2k3 Server). Everyone's user name and password were manually entered into the SNAP device, which allows them to map the network drive and access the files. On the problematic PC, after a few days, trying to open the mapped drive results in a "Network access is denied" error. Browsing to the SNAP server (i.e. via \\SNAP01) results in the same error. It seems that Windows 7 decides to stop using the user's credentials and switches to a PC-NAME$ account. I can log-in to the SNAP device and see all the connected users, and from this problem PC it shows user PC-NAME$ is logged-in as a guest. If we reboot the problem PC, it connects to the SNAP device using the user's credentials like all other PCs do. After a few days, pfft. I have tried to unmap and remap the network drive. Same problem after a few days. I even tried mapping with a different set of credentials (i.e. Administrator). Didn't work. Another problem that happens every few weeks on that PC is that multiple drive mappings to this SNAP server begin to appear. We have it manually mapped to Y:\ (not using any logon scripts), but sometimes extra copies of it appear under X:\, W:\, etc. This seems to occur in conjunction with the above problem. Another problem with this PC that happens nightly is with backups. On our server we have a backup script that simply copies files and folders of all PCs on the network via the administrative share at \\PC-NAME\D$ (copy all files from the D drive, with some exclusions). If I get on our server, I can browse via Windows Explorer to the problem PC and look at all the files on \\PC-NAME\D$. That night, the backup will be successful. However, the next night (and every subsequent night), access will be denied. When I manually browse to the problem PC again, it'll work again that night. This backup scheme works flawlessly on all our XP PCs and the other 3 Win7 PCs. Over the last couple months I have tried so many different things and searched the web far and wide for potential solutions. Posting here is my last resort before reinstalling Win7 from scratch on that PC hoping the problem goes away.

Hi, Did you check the credential manager on that problem Windows 7 machine? In Control Panel\Credential Manager, check if any incorrect credential saved on machine. Furthermore, you can try to temporally disable firewall for test. Regards, Leo HuangLeo Huang TechNet Community Support

Thank you for the response. Unfortunately, the credential manager is empty on all Windows 7 PCs, and the Windows Firewall is already disabled on all PCs. Regards, John

Hi John, I am experiencing a somewhat similar problem with a Windows 2008 R2 server and Win7 clients. In our case, the misbehaving drive will become inaccessible after the client has been running for a few hours. We have found that mapping the drive to the IP Address will work, and mapping the drive using the fully qualified domain name will work. ('net map F: \\123.45.67.89\share', or 'net map F: \\server.domain.com\share' will work, 'net map F: \\server\share' will not) What is really weird is that other shares on the same client and server are not affected.

what happens when you run \\server in run command?