If you are having problems connecting to a Windows 10 share from a Windows XP computer it is because Windows 10 is using SMB 2 while Windows XP uses SMB 1. Microsoft turned off SMB 1 because is has turned off SMB 1 since it has too many security holes.

But if you still need to connect a Windows XP computer to a Windows 10 share, you can turn on SMB 1.

1. Open Control Panel
2. Open Programs and Features
3. On the left click “Turn Windows features or or off”
4. Scroll down and look for “SMB 1.0/CIFS Files Sharing Support” and put a check mark in the box.
5. Click OK
6. Reboot the computer.