3rd party plugins list not loading

Hi,

I decided to activate Local Player plugin but when I clicked on the plugins tab nothing happened for a few minutes until it finally opened up but without 3rd party plugins list.
Tried restarting computer and LMS a few times and eventually installed 8.3. 3rd party list briefly appeared but disappeared when I exited plugins tab. Tried reinstalling 8.3 but problem persists.
Thanks,
Mike