Windows 11 Fail share between domain PC and workgroup PC

Hi Valentin,
The issue you're facing with accessing a shared folder on your upgraded Windows 10 domain PC from a Windows 11 workgroup PC is a common one related to changes in Windows 10's network sharing and security mechanisms compared to Windows 7.
Here are the key points and steps to help you resolve it:

• SMB Protocol Compatibility:
• Windows 10 disables SMBv1 by default because it's insecure, but older workgroup or non-domain PCs might only support SMBv1.
• Ensure SMBv1 client is enabled on the Windows 11 workgroup PC (if you trust your network), or better, enable SMBv2/3 compatibility on Windows 10 PC.
• To enable SMBv1 on Win 11: Go to "Turn Windows features on or off" and check "SMB 1.0/CIFS File Sharing Support".
• To disable SMBv1 completely and ensure SMBv2/3 are working, check the registry and services related to LanmanServer and SMB.
• Network Profile and Sharing Settings:
• On Windows 10 PC (domain joined), make sure the network profile is set to Private (not Public).
• Turn on Network Discovery and File and Printer Sharing in "Advanced sharing settings".
• Disable password protected sharing temporarily to test if permissions are the problem.
• Credentials and Permissions:
• For access between domain and workgroup PCs, credentials matter.
• Adding a user account matching the username and password on the domain PC to the workgroup PC (or vice versa) can help.
• On the shared folder, check both Share and Security permissions to ensure the appropriate groups/users have access.
• Adding "Everyone" with Read or Full Control permissions temporarily can help identify if permissions are the cause.
• Firewall and Antivirus:
• Temporarily disable firewalls on both ends or create exceptions for File and Printer Sharing.
• Some antivirus software may block SMB traffic.
• Access by IP:
• Instead of accessing the share by computer name, try using the IP address directly in File Explorer: \\ip-address\sharename.
• Remove and Rejoin Domain / Workgroup Interaction:
• You mentioned trying to remove and rejoin the domain on the Windows 10 PC with no success.
• This is expected if SMB protocol or sharing settings aren't aligned.
• Check Event Logs:
• On the Windows 10 PC, check Event Viewer for any SMB or network-related errors when the access fails.
• Additional Registry Tweaks:
• Sometimes increasing the IRPStackSize or enabling/disabling SMB2 via registry can help with these network share issues on Windows 10.
• For example, to disable SMB2 temporarily: set SMB2 DWORD to 0 under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters.

This problem is documented in multiple Windows Forum discussions, especially after upgrading from Win7 to Win10 where SMBv1 is disabled and network sharing behavior is tightened.
If you want detailed step-by-step instructions or registry changes based on missing permissions or SMB versions, I can provide those as well.
In summary, your likely solution path:

• Enable SMB1 client on Windows 11 workgroup PC or ensure SMB2/3 on Windows 10 domain PC.
• Verify network profiles and sharing settings.
• Adjust shares permissions to include "Everyone" temporarily.
• Test accessing via IP address.
• Check firewall and antivirus.
• Match user credentials between computers.

This combination should restore your ability to access shared folders across the domain and workgroup boundary despite the Windows upgrade changes.
If you can share the exact error message screenshot or the error code text (from your picture), I can give more targeted advice.
Reference similar issues and solutions can be found throughout WindowsForum threads on shared folder access errors after Windows upgrade, including SMB protocol problems and permission mismatches.
Let me know if you need help with any specific step!