BryceJ wrote:

I have been using Reaper v4.78/x64 for several years.

That is a very old version of Reaper — Reaper is on version 7.49 (as of this writing).

Reaper did not support VST3 until version 5. Since Pianoteq, beginning with version 9, no longer includes a VST2 plugin, you’ll either have to upgrade Reaper or stick with Pianoteq 8.

That is sort of what I thought. Thanks for the confirmation.

I have been using Reaper v4.78/x64 for several years.

That is a very old version of Reaper — Reaper is on version 7.49 (as of this writing).

Reaper did not support VST3 until version 5. Since Pianoteq, beginning with version 9, no longer includes a VST2 plugin, you’ll either have to upgrade Reaper or stick with Pianoteq 8.

I checked the C:\Program Files\Common Files\VST3 directory and the Pianoteq 9.vst3 is in the file along with all of the previous version's vst3 files.
Is the vst3 file not the file that is used for VSTi in this version of Reaper?

Older versions of Pianoteq also installed a Pianoteq.dll file in the C:\Program Files\Cakewalk\VstPlugins directory. There is no Pianoteq 9.dll in that directory. I renamed the Pianoteq 6 STAGE .dll file in the Cakewalk directory and that version of Pianoteq disappeared from the Virtual Instrument list. Is there no Pianoteq 9.dll?

Both of the directories I mentioned are searched by Reaper for VST plug-ins.

Any help would be appreciated.