Win10 can't connect to Win8.1 but Win8.1 can connect to Win10

>> what is the "file sync software" <<

The software is Free File Sync and while it's design, functionality, options and capabilities are excellent, imho, the "Free" and the payment options are misleading, so, I am not recommending it.  It is better than any of the many other file sync programs that I have researched and/or tested.

That, however, is moot.  My observation is that any file transfer action such as manually transferring a file using file explorer from the Win8.1 computer would have probably triggered Win10 to allow connections in the other direction.  Again, I am now more certain than ever that this is a user rights glitch within Win10.

I'm guessing that there are not that many users out there that don't login with admin rights if they have that option.  Logging normally in normally with non admin rights does give one at least a tad more sleep at night ;-)

Beverly

(1) That is pretty nice to hear. I hope it will last or that, as you say, you'll just have to redo it after the Win 10 does a reboot. But what is the "file sync software" on the Win8.1? Are you sharing the files & folders through OneDrive in some way? It does seem to confirm it is something about 8.1 causing the problem, even if it is triggered by a reboot of Win 10. 

(2) I kept clicking at that link I posted earlier & got to this...

https://support.microsoft.com/en-us/windows/file-sharing-over-a-network-in-windows-10-b58704b2-f53a-4b82-7bc1-80f9994725bf

File sharing over a network in Windows 10 I thought the section "How do I troubleshoot sharing files & folders?" is interesting, especially the part "Make sharing services start automatically". It's reminiscent of that FDResPub thread. But I don't know whether it will make a difference or is even worth messing with at this point. I hope what you have done will last.

Think this is designed to make sure users go crazy.

My primary need for network connections and file sharing between these two computers is to sync files so that I can work seamlessly on either computer...

So, I just ran my file sync software on the Win8.1 computer (which always works when the Win10 computer is turned on) completed the file sync, then climbed two flights of stairs (I'm getting too old for this) to the Win10 computer, clicked on the shortcut for the Win8.1 computer and had an immediate connection.

Perhaps the step that I missed was logging in as admin, then relogging in as the non admin user, but I didn't run a file transfer or file sync before I returned to the Win10 computer.  In most cases, rebooting does not prevent subsequent reconnections to the Win8.1 computer from the Win10 computer.

If history holds, I will now be able to connect from the Win10 computer until something such as a windows update runs a reboot.  Just updated my "tips" file to include this step next time.

Beverly Howard

>> I hope that leads to a solution <<

yep, been there before and this is not a homegroup issue... don't have homegroup on the Win8.1 computer.

I am pretty sure that this is a user rights issue since (for security reasons) the normal login on the Win8.1 computer is as a non-admin user.  There appears to be a glitch where the Win10 os "assumes" that non admin users are to clueless to know what a file transfer is.

Ironically, I had no problems with file transfers to and from the other win8.1 computer on this network, but that box is now gone.

...and, as mentioned, I had the ability to share files in both directions the day before I posted my last cry for help on April 10.

Will keep trying combinations.  Thanks for the response,

Beverly Howard

I think StephenHayward26 was referring to this...

https://support.microsoft.com/en-us/windows/homegroup-removed-from-windows-10-version-1803-07ca5db1-7bca-4d11-68a3-a31ff4a09979

HomeGroup removed from Windows 10 (Version 1803)

I hope that leads to a solution & gets you off McCartney's long & winding road. Have you run into him yet?