I get frequently errors when opening gui on Nectar3 og Neutron. Cubase just hangs and show error message.
Cubase 10.5.12.123 64bit 2020.5.20 0.14.51.410.dmp (1.97 MB)
Post a picture of your plugins page showing what version of Nectar and Neutron you are running. Izotope has a thing where it installs more than the single instance of the VST3 plugin - even if you tell the installer to install only the VST3 version. You might be using the VST2.4 version of the two plugins and you want to avoid those, this might be causing your issue.