Can't access Windows shares after Windows 10 build 1803 update

I have two Windows 10 computers on the same home network. Prior to the 1803 update I used to keep them in sync by sharing a folder on one, connecting to it on the other, and using sync software. The update has broken this.

Now I can always ping the other machine by IPv4 address, but most of the time pinging the hostname returns "Ping request could not find host $hostname". Occasionally it does work, and returns an IPv6 address.

So far, so annoying, but I could simply use the IP all the time in UNC paths instead of the hostname. However, even though I can ping the other machine, I cannot connect to the share. Trying to open \192.168.xxx.xxx through Explorer gets me a lengthy pause and then "Windows cannot access \192.168.xxx.xxx" with Error 0x80070035, "The network path was not found.".

How can I share files between the computers now?

Info that may be useful:

• Neither machine has ever had Homegroups enabled.
• The only firewall present is Windows Firewall. Avast anti-virus is present, with its firewall feature not installed. Disabling Avast does not help.
• I have different usernames on the two PCs. One is a local username, the other is tied to a Microsoft account. I do not get any box which would allow me to enter a username (it appears to be "can't see the PC" rather than "not authenticated").
• Enabling the "Function Discovery Resource Publication" service, as suggested by some sites, does not help, except that the machines can now see one another under "Network" in explorer. Seeing the other computer does not help with accessing it.
• Network discoverability is turned on on both, and they are both set to treat this network as a "private" one.
• I do not want to re-enable SMB 1. I understand that it was removed for good reasons, and that there should be other ways to share files!

Other SuperUser questions that are (probably) not dupes, but may be related:

• This question has a similar problem, though trying to connect to Samba shares rather than other Win10 ones, and only on machine that have had a "windows reset".
• This question appears similar, but while they have the same problem when using the hostname they are able to connect by typing the IP address.
• This question may actually be a dupe, but they have had the problem since Windows 7, wheras mine only started with this Win 10 update. Same symptoms, may or may not be the same underlying problem...

After quite a lot of wasted hours I found... maybe a solution, maybe more of a workaround, elseweb: turning off and on the association of File & Print Sharing with the network adapter on the target computer (the one whose share you're trying to connect to) appears to fix it. So far the fix has stuck for me, but others have reported it only lasting until the next reboot, or possibly (if on wifi) the next network change.

Cycling this can be put in a Powershell script:

Disable-NetAdapterBinding -name "adaptername" -ComponentID ms_server
Enable-NetAdapterBinding -name "adaptername" -ComponentID ms_server

Needs to be run as Administrator.