I thought I had seen a similar problem to this on 3.0 RC1 reported but I can’t find the post so apologies if duplicate.
I am trying to revert back to 2.9.1 from beta 3.0 RC2 but when I do Install 2.9.1 the App Structure panel will not load components and just displays the loading spinner, I cannot select any of the Add Component, Framework actions whilst in this state.
Creating a new project in 2.9.1 does not fix it, both existing and new projects show the issue. No errors shown in Terminal and system check reports all okay, experimental is turned off.
I have uninstalled beta, rebooted and installed 2.9.1 and has made no difference
Installing beta 3.0 RC2 again fixes it and everything works again but need to use on production site so need 2.9.1
Any ideas ?