Windows 10 share to MS-Dos 6.22 failing after an update from Windows 7

Solution 1:

Todd Wilcox has the answer. You will have to re-enable SMBv1 on that Windows 10 system. You can do this by going to Control Panel\Programs and Features, and selecting "Turn Windows features on and off" on the left side. Scroll down the list until you find "SMB 1.0/CIFS Server". You can enable CIFS Client too but it shouldn't be necessary.

Like Todd mentioned, using SMBv1 (as well as a DOS system) is VERY insecure and leaves your systems vulnerable to the WannaCry ransomware vulnerability. If this is on a corporate network you would do well to follow best practices and attempt to airgap those two systems at MINIMUM. If this is on your home LAN, well, best of luck!