I have installed the current beta on both max 2021 and max 2023.
Max 2021 works fine, however opening max 2023 throws up a loading error (attached)
Once I ok through the error in 2023, it seems to then work ok.
I have tried the above file changes suggested but that doesnt do anything.
Also my update manager shows an error (attached).
The Update Manager error was caused by a temporary problem in our server. It's already fixed.
Please, try running Update Manager manually from the Windows Start menu->Itoo Software.
Regarding the dlo error, that's strange. Because for Max 2022/2023, the plugin is not longer installed in the Max plugins folder, but at C:\ProgramData\Autodesk\ApplicationPlugins.
Please remove manually forestpackpro.dlo from the "plugins" folder, reinstall and check if file appears again.