Upon starting Logic X for the first time, it had to rescan all AUs, which of course invalidated Nebula3/Nebula3 Reverb. I force validated, relaunched, was prompted with the following screen but everything seems ok.
EDIT: did a quick play thru of a track. No problem. Inserted Nebula, bypassed it, changed presets... everything works fine.
One user with the same setup (using FrankydT/Gege's method) as me on gearslutz mentioned that running 10.9/Logic X, he is unable to edit parameters... when he changes a value and closes the window and then opens the Nebula3 window again, the value has changed back to default setting.
Installed Mavericks yesterday after a download time of around six hours !! But there is a problem with the Nebula GUI in Logic Pro X via 32 Lives. The faders do not move as you try to touch them, but if you bypass and then un-bypass then their positions jump to where you 'moved' them to. Not really able to work like this. I got a reply from Sound Radix saying they haven't 'tested or qualified' Mac OSX 10.9 and they do not recommend using 32 Lives with it ! They expect to release an update 'in a few weeks'! Luckily I can get my Nebula work done in Logic Pro 9 running 32 bit. I have Nebula 3 Pro, not Server, so do not have the 64 bit VST for Franky and Gege's workaround. Just letting everyone know the situation.
I'll test it. Starting downloading the thing. But I usually don't install new freshly released OS or software. I usually let pass a lot before upgrading. For audio work I'm still on Snow Leopard, I think I could may NOW pass to Mountain Lion. And I suggest to everyone to stick with their working setup, or at least to keep a backup. It seems Apple needs beta testers… (it's free, and many will fall in the trap)