When did it become S.O.P...

[cuttime]

...to have to restart the computer when installing or updating a plugin for it to be recognized? It seems that I've had to do this for about the last rear or so. Is this a Mac thing? An OS thing? A VST or AU thing? A DP thing? I don't recall ever having to do this before.

[dix]

It's not SOP here. Plugins show up normally after installing or updating in good ol 10.11.6. Same experience in Sierra and HS...as I recall before rolling back to El Cap.

[MIDI Life Crisis]

Sounds like it may have installed a helper app that needs to or WANTS to run at startup. Such apps or files can create problems. See if there’s an install receipt that states what was installed.

[mikehalloran]

When did it become S.O.P...

Normal with High Sierra on some apps—not many, though. I was surprised when I first noticed it—Finale, perhaps? Can't recall if DP 9.5.x gave me that.

Because of the eGPU issue, I am stuck at OS 10.13.3 so I don't know if this was addressed in 10.13.4–6.

[cuttime]

I just examined the .pkg contents of AAS player, and saw nothing that should launch on start (at least none that would seem to). Audio Modeling actually recommends a restart in their documentation.