This worked for me, and I'm quite the newbie to network admin. For other newbies, to add this key, go to start, type in regedit, open the app, navigate to the key
HKEY_CURRENT_USER\Network\
then look for the letter of the mapped drive (I only had the one anyway)
then click on edit, new, DWORD Value, change the name of the new value to ProviderFlags, set the value as decimal 1. Then close and re-boot.
I'd probably set a restore point before you do this, or export a backup of the registry, in case you mess it up. Unlikely though.
My problem had been that I have an old scanner still running on an XP machine, that cannot be upgraded, and the rest of my network is Windows 10. After the update the W10 machines could no longer access the mapped drive on
the XP machine, even with SMB1 options still set as they were before the upgrade. I rolled back to keep the business running until I could figure this out.
It's getting harder to keep that old scanner going but a new one is very expensive (medical x-rays from phosphor plates) and I'm retiring in the next 5 years. Of course the manufacturer long ago abandoned the scanner, and all
updates. The new ones do the exact same as the old ones, it's a grayscale image after all, nothing high tech there. I just wanted to explain why so many businesses still need things like a working XP 32bit machine, SMB1 access and so on.
Thanks for forums like this, since I can't call tech support and am on my own.