I've had the same problem, Windows 10 pc can see Windows 11 pc but not vice-versa, both in the same network. All the usual variables are good, i.e. network discovery, file sharing, password, etc. Yet no luck.
One thing worked, in the Win 11 computer (the one that can't see the Win 10 pc, I typed \ComputerName in the path bar at the top of the file explorer window. The Win 10 shares appeared. I then mapped the ones I wanted so they would always show up when I opened File Explorer.
I don't get it but it worked for me.
Thanks, Manny.
Can you verify your version of Win 11? What you describe here worked for me until 4 days ago when I upgraded to Win 11 24H2.
It seems with the latest upgrade Microsoft has filled the final gap in their attempts to make Win 11 and Win 10 completely incompatible on home networks.
What's most frustrating is the fact that I can RDP into that Win 10 machine. I just can directly access the shared file system.
Until they finished putting on the final touches to destroying home networking between Win 11 and any other Windows machine, these issues were primarily because the Microsoft Accounts that they have been hard-selling to use don't have local passwords. Because of that, you have to set the machine you want to access by turning off password protected sharing in the "All Networks" section of Advanced Sharing Settings.
For those who can see the computer in the Network list but still can't access it...
After 24H2, even turning off password protected sharing will fail because even if you can see the Win 10 computer in your Network list, you'll get the following error:
"Windows cannot access \computerName
Check the spelling of the name. Otherwise, there might be a problem with your network. To
try to identify and resolve network problems, click Diagnose."
What do mean, "Check the spelling"? I clicked on a computer name you already show in the network list!
Note: I've verified that Win 11 24H2 is the problem (at least for me) by backing out the upgrade and seeing the issue disappear.