Originally posted by don.desmarais:

I just started having this problem after I enabled push-to-talk in Steam chat to the middle mouse button. I have changed what key I use for push-to-talk in Steam chat settings, but Valheim just doesn't want to use my middle mouse button any longer for any task. Re-binding the secondary attack and deconstruct keys worked for these tasks, but map pings are still impossible.

Tried a reset to default?
Tried a file verify?
Library - game - right click game name for Properties - Local files - verify

Running mods?
Have a controller plugged in?
Anything else might be hijacking the middle mouse?