Same here (iMac 5K late 2014). If I remove the Nextcloud.app in the /Applications folder I can successfully install the legacy app by doing a right/ctrl-click on the installer and selecting “open”.
But now I have two problems: On start the app issues a push notification that there’s a new version (should know better that it is the latest version of the intentionally installed legacy version) and then crashes some seconds later, only to be automatically restarted again. And again. And again…
While typing this I had to click dozens of times into the text field in order to reset the keyboard focus here. Quitting the app manually does not help as it is restarted again by the system. I need to remove or rename the app to prevent the restart cycle.
Needless to say I now have a massive problem working with my files without a usable Nextcloud client.
PS: I now have tried the 2.6.2 version also, same effects.
PPS: Same for an old 2.5.1 I had laying around in my Downloads folder. I start to wonder if it is the driver or the local files.
I don’t have the restart issues but my NextCloud logo is vanished from the menubar so I can’t alter settings or check if the sync is working.
What happened that this is so mashed up suddenly?