Admittedly I have a crap load of plugins but try as I might I cannot get SPLAT to get through a total rescan of existing plugins.  I have removed or deleted all problematic plugins that threw up error messages from their respective folders but every scan ends in a hang on random plugins on each new scan.  Arturia seems the worst culprit...but again...it hangs on different plugins on each scan.  
 
What, exactly, does a "reset" of the vst plugins do?  I'm afraid to do that if I can't totally rescan all my plugs.
 
This all started when I installed the new Waves Smack Attack.  It installed fine and is right where it should be and I think SPLAT even sees it.  But it does not show up in the Plugin Manager so I can't use it.
 
It's not worth crashing my whole VST setup over but I'd like to get it working if possible.
 
I have an extensive custom folder setup for all my VSTs and don't wish to have to rebuild that.  Oh my gawd no!!  
 
Throw me a clue, will ya??
 

Hi. Unless you use Vst3, I believe you will have to add Programfiles (X86), Waves to your scan list.
It references the Waveshell from there*, if I understand correctly.
All the best.
Edit: *That includes the 64 bit versions.

When I have trouble seeing installed plugs, I toggle the display filter in the plug in list. IF it's usually listing them by type, try listing them by manufacturer. It's worked for me a few times in the past.

A reset clears the VST Inventory in the registry and then runs a scan.
 
If the scan options "Rescan Failed Plug-ins" or "Rescan existing plug-ins" are enabled, they should be turned off, These options should be used sparingly with manual scans to solve specific problems. Leaving these options enabled make the scanner work harder than necessary.
 
Some scan errors can be ignored. If I get an error on a plug-in that I know to be good, I enable the plug-in and let the scan continue. Rarely do I disable plug-ins while scanning. Often plug-in errors are the result of a previously scanned plug-in trashing memory.
 
A scan log may help. To create the log hold the SHiFT key while pressing the Scan or Reset button in Preferences > File > VST Settings. It may be necessary to scan incrementally to get a complete scan. This may be done by modifying the scan path or temporarily moving parts of the plug-in directory tree(s) out of the scan path adding them back slowly after each completed scan. I prefer to move entire folders instead of individual plug-ins because it is easier to remember where the folders go.