obviously UAD and 32bit 
But what other malicious criteria makes plugs appear on this list?
Check this out and also don’t forget to check run in existing auhost in jbridge for every bridged UAD instance
Hi Raphie,
quoting a developer:
In order to improve the overall stability of our sequencer applications we will introduce a Plug-in Scanner which scans every plug-in (only 64-Bit) in its own process. This occurs during the start-up phase of the sequencer, or in the case of a plug-in re-scan is initiated by the user, from within the sequencer application.
Plug-ins that crash during the plug-in scan will get added to a black-list, and are excluded from the sequencer environment.
To ensure your plug-ins will be readily available to users in our future sequencer releases, we encourage you to verify your plug-in’s operation with our Plug-in Scanner. In order to achieve this as efficiently as possible, we are providing you with a 64-Bit VST3 and VST2 command line app for Windows and OSX.
On OSX, we perform a check that intentionally leads to a crash, to identify if your plug-in is affected by an Objective-C runtime corruption bug in the OSX System.What do you have to do if your plug-in crashes on OSX during the scan process?
As far as we know these plug-ins are built with Deployment Target 10.7.
There are two options to fix the problem:
- Set the Deployment Target of your plug-in to at least Version 10.8
- Uncheck the „Implicitly Link Objective-C runtime Library“ in the Xcode Project settings.
When you rebuild your plug-in with these settings the crash should no longer happen and your plug-in should pass the scan process successfully.
We have already informed Apple about this bug.
East West Play 5 was just blacklisted here! I reactivated successfully but it shows up red in the plugin manager
This is excellent news, time for the developpers to step up their game. thnX!
why are izotope products blacklisted for me? (edit i see only the VST2 version is blacklist, the VST3 version is still working)
play 5 not working in cubase 9.
I’m seeing 64-bit plugins being blacklisted.
I’ll also add that it is infuriating that older Steinberg plugins from earlier versions of Cubase - that I still use - and never updated to 64-bit are blocked. The only option will be to see if jBridge will work on Steinberg plugins.
Clearly, C9 will not be the only version I have installed fore the foreseeable future. 
Yes, iZotope VST2 get often blacklisted. Last time I spoke to engineering, they were aware of it, but was not clear if they had to contact iZotope or needed to ‘tune’ the scanner. They were already in contact with EW - if you re-enable PLAY 5, it should work fine.
64-bit plug-ins can also crash and be blacklisted, indeed.
Several developers have been directly informed (some have updates ready) and given the tools to find potential issues.
You can reactivate this
So what is the news about UAD? Raphie is saying they have been blacklisted for him? UAD are in all my projects - fine I will wait until this has been sorted.
Guitar Rig 5 is black listed which I found rather surprising…but to be honest I no longer care because I have an Axe FX
These are the blacklisted ones I see. Not a big deal for any of them as I do not use them much.
Curious why they are however.
UAD is blacklisted? As in UAD-2?
I won’t be able to use Cubase 9 if so.
Please tell me it ain’t so!
I don’t use UAD, but several users reported this. Not sure what version and/or 32bit.
Play 5 blacklisted here, but it unblacklisted OK
Jamstix user reporting blacklist on their forum.
Why does Cubase 9 feel it needs to blacklist programs that work fine in Cubase 8.5 (east-west, izotope, Jamstix, etc.)?
I see a Blacklist sale coming soon with C9 users ditching their blacklisted plugins cheap!
If plug-ins get blacklisted, it means they crash the scanner on start. The Sentinel is not even incredibly strict. In fact, I have a few plugs known to not scale really well or prone to cause possible RAM corruption at high track counts which pass the scan. VST2 iZotope plug-ins is know by both Steinberg and iZotope, our devs are also in touch with East West since before the release of Pro 9.
Please, see the first quote in my first post here.
ArtsAcoustic CL1 is the most unstable plugin I have used and it passes the scan. Though as soon as you try to load it, it crashes Cubase, hahaha
I actually wish this check was even more strict and picked up any plugins that could potentially be unstable. I have no room for unstable plugins in my setup and I’m sure many here don’t either.