The only thing I would change from the above post is that VS2 does not work.  If you select the "Easy Install" it WILL install VS2 as well and will default to VS2.  I was told by iZotope support to use the "custom install
' and ONLY select VS3.

I can understand iZotope trying different ways to solve this until they come up with an update or something. I'll just have to wait to see how my system responds when I'm back in a few weeks... Since I travel so much I should probably consider a mobile rig for mixing...

I'm having similar problems with Neutron Advanced.
Thanks for the tip about the VST2 versions which are completely unusable.
The VST3 version seems better but Track Assistant is very flaky!
 
I added 4 instances of Neutron to drums, guitar1 and 2 and bass.
Track Assistant worked fine on drums. 
On Guitar 1 TA runs and makes adjustments but then locks up until Sonar stops at Project End (glad I had that set).
Same story on the other tracks. Hit play again and same story - cannot do anything until it stops at the end of the tracks (4 mins 30 sec for this song). Very tedious! 
 
I have checked and do have the paramz file mentioned above. 
 
So is the best thing I can do next to install the normal version of Neutron (not advanced)?
Any suggestions gratefully received.
 
ZT

ZincTrumpet
I'm having similar problems with Neutron Advanced.
Thanks for the tip about the VST2 versions which are completely unusable.
The VST3 version seems better but Track Assistant is very flaky!
 
I added 4 instances of Neutron to drums, guitar1 and 2 and bass.
Track Assistant worked fine on drums. 
On Guitar 1 TA runs and makes adjustments but then locks up until Sonar stops at Project End (glad I had that set).
Same story on the other tracks. Hit play again and same story - cannot do anything until it stops at the end of the tracks (4 mins 30 sec for this song). Very tedious! 
 
I have checked and do have the paramz file mentioned above. 
 
So is the best thing I can do next to install the normal version of Neutron (not advanced)?
Any suggestions gratefully received.
 
ZT

Have you tried increasing the audio interface buffer size yet?  Neutron and other iZotope plugins run better for me if I have a higher buffer size set on my audio interface.

Thanks amiller, I already increased it from 64 to 192 but I will try higher.

ZT

Hi Art... Given that you're running multiple instances flawlessly and Neutron is apparently a resource hog, curious to know your rig specs. What's your computer setup? Thanks...

VST 3 solved the problem for me. HOWEVER, I was already close to my limit with plugins so I had to delete a few hogs.