FL Studio's plugin manager is not up to date with the latest versions of the SDK.
This was taken from the page "VST 3 Locations / Format" in the SDK documentation:
[quote]
On the Windows platform a VST 3 Plug ...
forum FL Studio 10.
I installed Wavesfactory Trackspacer2 (on Windows7 64bit).
I Installed VST2.4 (32bit) and VST3 (32bit and 64bit) of that plugin.
I opened FL Studio 10, and after I scanned for new plugins(a few times) only the VST2.4 ...
forum FL Forum via the FL Studio form, but that will not allow me access to the Forum.
As of this writing, I've contacted Tech Support through the Ticket process and am waiting on a response, but if anyone has a solution ...
forum