I have GP installed on both my PC and laptop.
I noticed that some plugins don’t show on my laptop anymore, like NI reaktor, BBC symphony and some more.
I may have removed some plugins in the plugin manager but i tried to reread all plugins within the plugin manager but did not find anything.
I am not home typically during weekends so i cannot check now.
Do you have any idea how i can see and use the plugins again?
Reinstall?
Remember the paths and add them in the Plugin Manager.
I will recheck next week… Some are just without an install, only copying files and thought i set the correct plugin folder locations, but i will recheck.
In my experience the “just copying the files” approach works for some VSTs and not others. Some require additional files in folders that you may not know exist, and others require Registry keys.
Maybe I indeed missed some original installers and just copied the file structure.
I will reinstall it properly install them again.
I tried reinstalling, but I’m afraid I’m missing still a lot of plugins.
I reinstalled all failing Native Instrument Komplete VSTi’s, and all VST (but not the VST3) are still failing:
I think all folders for plugins are set correct…
But if someone knows why all VST are invisible in the plugin manager, but VST3’s are not, please let me know 
I just by typing my question found the problem.
It seems they all are in the Vst64 directory … I initially thought that VST was 32 bit, and VST3 64 bit, but maybe I’m wrong (probably I am wrong).
Now I just put both the Vst32 and Vst64 directory in both the VST and VST3 search folders, and it works.
Yes, you are wrong. A VST plugin can be both 32-bit or 64-bit.
Yes indeed … I made a bit of mess of my plugins structure, but it’s ok … everything is found again
Best if you would go through the bottom part of the Plugin Manager’s list where all the plugins which couldn’t be loaded are marked red… then right click each one of those entries, jump over to the corresponding install folder and delete all of the 32bit versions, since Gig Performer won’t load them anyway. (Except you’d need them for other DAWs you are using).
Thanks for that idea, it will clean up my directories indeed.
I’m not using a DAW (maybe at a later time), but live performing is my main goal.
Yeah, then there’s nothing that would keep you from getting rid of all the 32bit versions. 
Great, maybe on my PC (not the laptop I use for live music), I will then keep the 32 bits versions.
If you don’t have a 32-bit DAW currently, there’s no reason to keep the 32-bit versions. Any DAW you might buy in the future will be 64-bit, so still no reason to leave them installed.
I know Band in a Box is now available in 64-bit (that’s what I’m using), but I don’t know if they have updated Real Band (a simple DAW that comes with Band in a Box, but I don’t install it). That might be the only exception.
In addition to deleting the 32-bit plugins (check both VSTPlugins and Steinberg/VstPlugins), a bunch of plugin installers also install the AAX versions (for Pro sTools (misspelling intended)) under the Common Files/Avid/Audio/Plug-Ins directory in both 64-bit and 32-bit Program Files and Program Files (x86). You can delete all of those as well.
Thanks, I will do a cleanup, I indeed see there is no need for 32 bit plugins to keep (and protools).