How to connect Windows 11 Pro to Server 2012 r2

Hello Bjorn,

Thank you for posting question on Microsoft Windows Forum.

Based on the issue description, the potential cause for the issue is that Modern versions of Windows often disable or remove the SMBv1 protocol due to security vulnerabilities. However, Windows Server 2012 R2 might still rely on it for network discovery or sharing. Since the connection was working before, any potential Windows update might have disabled this feature.

You can try the following suggestions for potentially fixing the issue.

1.Enable SMB 1.0/CIFS File Sharing Support.

• Press the Windows Key + R to open the Run dialog.
• Type optionalfeatures.exe and press Enter.
• In the "Windows Features" window, scroll down and find "SMB 1.0/CIFS File Sharing Support."
• Click the checkbox to enable it. If it's already checked, try unchecking it, restarting, and then re-checking it.
• Click OK and restart your computer when prompted.

2.Check Network Discovery and Sharing Settings.

• Open Advanced Sharing Settings:
  • Go to Settings > Network & internet > Advanced network settings.
  • Click on Advanced sharing settings.
• Configure Network Profile:
  • Under "Private networks" (which should be your office network profile), make sure that:
    • Network discovery is turned On.
    • File and printer sharing is turned On.

3.Verify Essential Services are Running.

• Open the Services App:
  • Press Windows Key + R, type services.msc, and press Enter.
• Check the Status of These Services are running.
  • Function Discovery Provider Host
  • Function Discovery Resource Publication
  • SSDP Discovery
  • UPnP Device Host
  • 

4.Manually Map the Network Drive.

• Open File Explorer.
• Right-click on "This PC" and select "Map network drive...".
• Choose a drive letter.
• In the "Folder" box, type the path to your server's shared folder. Use the format \ServerName\ShareName
• Check the box for "Reconnect at sign-in".
• Click Finish.
• If prompted for credentials, enter the username and password you use to log in to the server.

Hope the above information is helpful! If it is. Free feel to hit "Accepted" for benefitting others in community having the same issue too.