In Computer, some network drives may have a red cross in the icon indicating that a network drive hasn’t connected properly. However when you access them, they work perfectly fine. This problem might happen if:

• you logoff and logon the computer.
• you don’t select the Remember my password option when entering credentials
• the network drive is mapped using alternate credentials that were used to logon with

This is because the main icon library file (shell32.dll) updates the network drive icon only in the details pane of Windows Explorer, and not applied to the Folders area of the window.

An update is only available from Microsoft directly if you ask for it (silly I know, but it’ll be made available as a hotfix soon enough). You can find this information here.