. . . . So, that used to work... now all it says is Error x8004e204 (message missing). . . .
Given that the program was working, then suddenly starts failing with a Windows error code would suggest there has been a Windows update which has broken something.
Try running a full system check - see this tutorial.
If the check finds and repairs errors in Windows and Acid still has issues, were there any other changes on the PC between working/not working?
Have you posted in the Native Instruments Izotope forum?
So... I found a work around... (I also own SOUDFORGE, which uses also the same VST scan software - Neutron still worked fine in SOUNDFORGE - I did a switcheroo of the 4 little software scanner (changed the names) and... IT WORKED !) So the problem is the scanning process - even though I reinstalled about a 1000 times - and erased and all. So at least it's back... SELL THE SOFTWARE to a company that would care about it... and its customers ! Geez !