I have the same issue in Halion 6. This is what happened:
I converted old FXB files to Halions VSTPRESET. Around 350 in total. I then tagged them all in Halions Media Bay, which took days. I then wanted to batch rename (the name) which I did outside of Halion by renaming the filename file browser. I then re-registered the VSTPRESET files in Media Bay, which worked fine. I can now see the files Halion 6 (name in display does not reflect filename any longer - which it does in Media Bay) and the presets cannot be loaded any longer. If I do, I get the same error message below and Halion crashed:
“The preset could not be loaded. This can happen if the preset Halion …”
This is about the 3rd time I have to start all over, reload all my FXBs AGAIN, retag them AGAIN and so on.