I have some songs from Cubase 8.5 with all these Prologue parts and now that is gone. Was there some kind of transition to similar patches, as I have no idea which sounds they once had?
You can find and download the old plugins. There’s a thread here about that. I’ll see if I can find it.
I don’t have 8.5 but in Cubase 11 one can copy this file
C:\Program Files\Steinberg\Cubase 11\VST3\SynthEngine.vst3
to
C:\Program Files\Steinberg\Cubase 14\VST3.
This works for me. As always, YMMV.
I can load the synths and get them to work for old projects. But the issue I run into is that the preset folders are empty.
Is there some secret place the original presets are located so I can move them to C:\Users\your_username*\Documents\VST3 Presets\Steinberg Media Technologies?
My (very old - 2011!) user presets are in my Documents folder:
G:\Documents\VST3 Presets\Steinberg Media Technologies\Prologue
I don’t know where the Steinberg ones are - they just appear in the “Open Preset” dialogue.
I moved from 8.5 to 13 on a newer computer. I went to the VST3 folder as suggested, but don’t see the same thing. I looked into vintage -plugins , and went down a few levels to the vintageplugins shown in 2nd picture. But I couldn’t copy, only copy path, and couldn’t paste into the VST3 folder.

As I said, I don’t have 8.5 installed. But here are 9.5 and 11, and 14 after copying. You will get a “Administrator Permission Required” dialogue, but I just click “Continue” and the file gets copied.
So I was thinking that since these are on the C drive, they weren’t transfered when I updated Cubase from 8.5 on the win 7 computer to C13 on the Win 11 one. So I went to the win 7 computer and unfortunately, though I had looked at things on it less than a week ago, now I can’t get to go to Windows, just stuck on the 1st screen. Other times when it might stick there, I’d disconnect a UBS or something and then it would continue but now, not happening. Before the end of the year, I had just done the procedure that would make that version work still when the dongle wouldn’t and it succeeded.
So today, I got the idea of putting the Win7 Ultimate in that computer. I’m not sure if it actually accessed it, as it didn’t ask if I wanted to repair or anything. seemed like it just decided to come back to life today. So I looked into the VST3 folder and copied the whole folder to a flash drive. (thinking maybe there are other things I might want. It didn’t ask for any permission. I went to the C13 computer and put in the VST3 folder and opened the song with Prologue but it still said they were missing.
Back on the win 7 computer, I put the dongle back and reconnected 2 FS Projects, and opened the same song. the Prologue tracks definitely play but I had to reconfigure the routing before I could hear the sounds. I thought maybe I just need to copy the one synth engine file, again it didn’t ask for permission. I went to overwrite the previous synthengine, but could see they were the same at ~15meg. I thought maybe I needed to restart Cubase, so closed it but it wouldn’t reopen. 3 of 4 instances in task manager closed, but one won’t, as usual, meaning I have to reboot. I will see what happens after I do so.