Check that the computer or NAS hosting the share is on and reachable, then check credentials. A mapped drive often fails after a password change, a server restart, or a Windows update that changed sharing settings.
Common causes
Host computer or NAS offline
If the device sharing the files is off, asleep, or disconnected, the share can't be reached.
Saved password out of date
After a password change, Windows keeps trying the old saved credentials.
Name doesn't resolve
If the server name can't be found but its IP address works, DNS or name resolution is the problem.
Old SMB version
Older NAS devices use SMB1, which modern Windows disables for security.
Network profile set to Public
Windows restricts sharing on networks marked Public.
How to fix it, step by step
- 1
Confirm the host is online
Make sure the server, NAS, or sharing computer is on and connected.
- 2
Try the IP address
In File Explorer, type \\ followed by the host's IP address. If that works, fix name resolution.
- 3
Update saved credentials
Open Credential Manager, remove old entries for the server, and reconnect with the current password.
- 4
Set the network to Private
In Windows network settings, set the office network profile to Private.
- 5
Remap the drive
Disconnect the mapped drive and map it again, checking "Reconnect at sign-in".
When to call a technician
If files are stored on an old NAS or a desktop acting as a server, it may be time for a more reliable setup — such as SharePoint/OneDrive or a properly backed-up NAS. We fix the access problem and help you choose a better long-term option.
On-site support across Orange County · see our business networking and WiFi installation services.
Frequently asked questions
Why does my mapped drive have a red X?
Windows couldn't reconnect at sign-in. The server may have been offline, or credentials expired. Opening the drive often reconnects it.
Why does Windows ask for a network password?
The sharing device requires credentials, or the saved ones are wrong. Use an account that exists on the server or NAS.
Should we move shared files to the cloud?
For many small offices, SharePoint or OneDrive is more reliable and easier to access remotely than an old NAS.