We are testing using Sandboxie to isolate Quickbooks on a Windows Server 2008R2 64bit terminal server and we have ran into a issue with mapped network drives. We have been testing for the last 2 weeks slowly adding users and did not have a issue until yesterday. The issue we are having is that the network drives inside of the sandbox are showing up but they have a red X on them saying they are disconnected and will not reconnect. Outside the sandbox they work fine. We rebooted the server and they started to work again for it looks like everyone but the Administrator. During the reboot I updated Sandboxie to 3.58 from 3.56 and that did not fix the issue. Does anyone have any ideas?

Programs in the sandbox can't establish the connection to network drives but they should be able to use an existing connection if the network drive was first accessed outside the sandbox.

Does this sound useful? You say the drives work outside the sandbox but is it possible the connection was established after the program started running in the sandbox and therefore the program in the sandbox did not use the established connection?

Or in other words: When you experience this problem, try to close the sandboxed program, then explore into the network drive from outside the sandbox (to establish the connection), and then finally restart the program in the sandbox, does this fix the program?

Yeah that is what I tried. I close all applications in the sandbox. Verify I can get to the mapped drive outside of the sandbox. Start a application in the sandbox and then when I try to go to the mapped drive it has the red X on it and then says "An error occurred while reconnecting P: to \\blah\blah" Microsoft Windows Network: The local device name is already in use" Like I said it is only happening to the Administrator account at this moment. Have anymore ideas where I can look?

Perhaps if you give programs in the sandbox full access to the file sharing subsystem then it would work better?

Go to Sandbox Settings > Resource Access > File Access > Full Access
and add the items
\Device\Mup
\Device\LanmanRedirector

Might be enough to add just the Mup one. Please check if this makes any difference.

Okay tried that and it did not make a difference. Its odd that it seems to only be happening to people that are administrators on the machine and it is any network drive I map.

Maybe this has something to do with UAC? Also, are you talking about some user account with Administrator privileges or are you talking about the built-in Administrator account?

It is the domain administrator account and the local administrator account. I will check to see if UAC is disabled and if it isn't I will disable it.

In version 3.63.01, a program in the sandbox should be able to reconnect to an existing network share.

Note that this functionality is blocked when the path \Device\Mup appears in the list of blocked resources in Sandbox Settings > Resource Access > File Access > Blocked Access.