I just installed a few stacks one by one and restarted RW8.51 with Stacks 4.2.4 after each install.
However, the stacks don’t appear on the list of stacks but I can see them in
/Users/applemac/Library/Group Containers/P97H7FTHWN.com.realmacsoftware.rapidweaver/Library/Application Support/Addons/Stacks folder together with the other stacks.
The only other thing to check is that the filenames of the stacks you expect to see are correct in that folder and not duplicated or altered. I presume that you’ve done this though. Restart the computer?
However, the stacks in question were all sent to me via Dropbox to view content in a project file they sent me.
I checked 2 of the stacks and there is nothing inside them except a Contents/Resources folder with zero size css and html file. So looks like they were corrupted somehow. I see if I can get then zipped up first.
Depending on how they were shared, it’s very possible that the shared file was created before the actual files themselves were fully sync’d to Dropbox.
I share files using Dropbox file transfer feature and had something similar happen before. Then I realise I was getting the transfer link before the file 100% sync’d. Which in effect meant DB was creating a sharable file from a partially synchronized file, so it wasn’t working.