Having the same issue
Extension manager empty. Double click on a .bex file to install, and I get the message about installing over the existing installation, but still nothing shows up.
Reinstalled Blocs; tried that one.
Remove brick from application support library; tried that too.
Tried on another laptop; no joy.
Also I have a block in the layer tree, shows on preview/export but not on the canvas (all viewport options on and no hide ‘eye symbol’ options selected in the tree. Probably something silly.
Any clues?
Thanks,
Andy.