Repost from http://social.answers.microsoft.com/Forums/en-US/w7network/thread/5f84c3dc-f1a9-4a2c-b74b-cc8382509748 Office Network with 10-20 PCs 5 Running Windows 7 Rest on XP SP 3 Sharing enabled, firewalls allow file transfer, sharing, etc After 1-30 hours Windows XP PCs are not able to access Win 7 PCs on the network. Messages are "you do not have permissions to access this resource" to "This drive is disconnected" to "File disc error" Timing is random, I have increased IPRStack size, added everyone to security, tried advanced sharing share, normal sharing, etc XPs can connect and everything is normal until it randomly disconnects them from Windows 7 - Windows 7 PCs are still able to access any XP PCs afterwards I've tried all and every configuration and after many hours of trying to find an answer - this is where I'm asking this question.

This is pretty much my situation too. I;m about to give up. My post is here. http://social.technet.microsoft.com/Forums/en-GB/w7itpronetworking/thread/e3990f65-bc99-494d-a27c-632733b74e2d Everything works fine all day long, 17 systems mixed XP pro and Win7 pro. Almost every morning the seven XP computers (CAD systems) with mapped drives to the Win 7 system can not connect., Rebooting the Win 7 computer being shared always fixes the problem. There are no problems with the Win 7 PCs connecting. Strange,, everything worked perfectly for 8 months, all systems being XP except the shared Win 7 system. This only started after I replaced some XP systems with Windows 7s. Even stranger everything works perfectly all work day. I now have Synology NAS acting as a file server for all 17 computer's office documents, everything on that side works great including speedy file access. If I can’t solve this soon I’m going to add a second Synology NAS for the CAD system. Seems they do a tango with all flavors of Windows without issues and the Synology Data Replicator backup alone was worth the price I paid for the NAS.

Some good points - especially the reminder that a server acting as the main file hub could be the only long-term viable solution. In reading your thread I've ran across some replies that suggested some things I have already tried & still had no resolution to the random access drops from XP -> Win 7 XPs are STILL able to ping Windows 7 even when they are no longer able to access the files. I tried no passwords/passwords/same passwords and none of these options solved random disconnects. & of course the real problem with this issue is troubleshooting it because no matter what changes you make you can only see if they take place the next time XPs drop the mapped Windows 7 so calibrating what works and what doesn't takes weeks. Still awaiting for any suggestions/solutions besides perhaps that this is an internal strategic initiative by Microsoft to have us switch all PCs to Windows 7...

Blame it on Extraneous Electronic Phenomena. Would you believe that I was moving this client off of a SCO server because authentication was a known issue with Win 7. They won’t switch 100% to 7 because they have several very expensive HP plotters that are not compatible with Windows 7. I also have another client in Michigan with the same issue only not as bad. He has a few Vista computers that don’t have the issue, again its only XP. He has to reboot about one a week. This is very discouraging, tried all the tricks, and as you say you can only see if something works if the XPs don’t lose access down the road. $600 for a second NAS seems the logical next move for me. Hmmm, maybe just move everyone to the current one and see how it performs. Nothing against Win 7, I do like it, its just not fitting in this role ATM.

Well, here is another I stumbled across at another forum.............. (not sure I cant post the link here) Windows XP losing access to Windows 7 shares overnight I have a Windows 7 Home machine (upgraded from Vista) with multiple file and printer shares. All shares are accessible with no problems by other machines running 7 or Vista. I also have a Windows XP machine that is able to access the shares for a while, but after several hours (usually overnight) the shares are no longer accessible (although I can ping the Win 7 machine). The shares still work fine from the other Win 7 and Vista machines. Oddly, the XP box can still access a share on a different Win 7 machine (running Ultimate edition). When I reboot the Win 7 Home machine, the shares are again accessible from the XP machine. Tidbits that may or may not be relevant: All machines have latest updates applied All machines are assigned to a workgroup with the same name Windows 7 machines are configured to operate on a “work network” (not a homegroup) On network card, tried disabling “allow device to be turned off to save power” Tried disabling “tcp auto tuning" Tried disabling “receive side scaling” I've tried to find differences between the Win 7 Home config and the Win 7 Ultimate config (since it doesn't seem to have the problem) . . . but to no avail. Any ideas?

VR TT Are you by chance running gbridge on the Win 7?

Very good suggestion - looks very promising just need to config router/pcs to install it & test it Thanks man

Well, again this morning, after trying everything I gleaned from this forum and others and my 32 years in the industry I pretty much give up. Time is too valuable to waste when there are other options. Win 7 and XP just don’t like to tango I guess, at least for me anyway. Now where is that Byte Bat I put away a few years back?