Why are my free 'iZotope' plugins being added to a "blocklist"? What to do?

I have the ‘iZotope’ Vst manager, and I installed 3 free plugins (‘Relay’, ‘Vinyl’ & ‘Vocal Doubler’) Unlike the rest, when I open ‘Cubase 13 Pro’ I get this warning:
“The following plug-ins have been added to a Blocklist:” (Naming all 3 above Vst’s)
Any idea how to fix it or what it means? Any help would be great. Thank you


When you install a plug-in and start Cubase, Cubase runs some tests on the plug-in. If the tests fail, Cubase puts the plug-in into the blocklist. This prevents Cubase from crashing or failing with a buggy/unstable plug-in.

Get in contact with iZotope and ask them to fix their plug-ins.

With Izotope it happens that they store the dlls as well as the VSTs in the respective folders. Cubase will put the dll onto the blocklist. Can you find the VSTs when you try to insert them? In that case you could ignore the blocklist…


Do you mean the “DLL” of the VST2 plug-in (*.dll extension) and the “VST” of the VST3 plug-in (*.vst3 extension)?

If Cubase finds both versions of the same plug-in, it shows only the VST3 version to let the users to use the latest and modern version only.

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I have most of the paid Izotope products, so just went ahead and installed Vinyl and Doubler via the Product Manager to check, and even though CB gives a warning about these Izotope plugins not being valid pluins on first run after installation, Plugin Manager shows both the 2.4 and 3.7.1 being available.

You don’t happen to have a customised Plugin Collection defined in Plugin Manager? In that case the plugins won’t appear on your list until you actually add them into your collection through Plugin Manager.

Izotope Product Manager does actually add VST2 and VST3 files in to the same directory in Program Files/Common Files/VST3 which is unusual. And for as long as I have been using Izotope software with Cubase (Many years) it has always given a warning about VST2 plugs being blacklisted, but they are always available once Cubase is up and running.

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Good call, thanks… Will do

Okay, when I’m in the studio next I’ll check if I can find them and if so just disregard. It may be a few days until I can check b/c I just caught ‘Covid’… Thanks again for helping

Okay, thanks for helping. I’ll double-check everything in a few days when I’m back at the studio and if I run into any more issues or discover anything, I’ll let you know