PT and Reaper

Thanks. I had just posted my issue on the Reaper forum! I don't use any other piano program.

Hi aWc, I'd guess this issue could be interesting to Modartt if turns out it's a thing they can implement a solution for.

Hope you get it working.

There are a lot of possibilities - I'm not expert with Reaper and it's settings are very extensive.

First thing to mind since on Mac, is in(Options/Preferences) choosing "Plug-ins/Compatibility" change "VST bridging/firewalling" to "Only Native" rather than "Automatic bridging (when required)". But if it doesn't help, I'd try also the other options here (separate and dedicated processes) before moving on to other things.

Also in the 'Compatibility' section, try deselecting "Pre-zeroing plug-in output buffers" and also uncheck "Reduce denormalization from plug-ins". Maybe, in Mac these Reaper helpers may failing to parse correctly (not sure if that makes it a Mac, Reaper or Pianoteq issue - but could be a nice thing to test). Maybe Pianoteq doesn't send this extraneous info too - in which case, maybe just on Mac, this setting fails over and causes the glitch when looking for non existent data.

Since you're working with multi track midi files, in the settings box, on left, choosing 'MIDI', on the right I'd look at things like:

"Create new MIDI items as" - set to ".MID files" (rather than MIDI items). Just in case it's this simple (handling of midi files on a different drive or where other things which should be beneficial become bottlenecks - may be some issues in importing multichannel midi whilst Reaper is making them into proprietary "MIDI items" on Mac - worth a shot).

"Import multichannel MIDI files" set to "as single channel items on multiple tracks" (rather than "always prompt...") in case some code forking blob stalls waiting for your optional input.

Try checking the box: "Handle type 0 MIDI files containing meta-events as if they were multichannel MIDI files" - in case some logic overlaps in regards to your multi chan setups.

Also on left, further down, select "VST" settings, on the right try:

Check the paths to your VSTs in the box displaying them - even if they look right - definitely still try clicking the "Clear cache/re-scan" button (A lot of DAWs require a similar rescan in certain circumstances such as when you have two identical plugin names. Recently this happened to me, as an example, demo plugins were used, tested then purchased but Ableton required a rescan to recognise the change because like Reaper, it reads the first and discards later 'versions' of the same plugin name - I vaguely remember similar issues back in the 90s with some other DAWs.

Try Reaper's vanilla UI option for plugins by selecting the box "Default VST to generic UI (instead of plug-in UI)". You get a list of editable items but without the original interface - it's a bit austere but you can also one-click toggle between it and Pianoteq's normal interface (for doing things like choosing your piano) - then maybe consider toggling to no UI for when recording/playing back only. (not best solution but in case it's a very Mac specific UI handing bug in Reaper or Pianoteq - hopefully if it's this solution, it could point Modartt to something they might be able to alter in a future update).

Also check box "Bypass audio while opening plug-in config window" - can't hurt.

And others, like maybe try in "Keyboard/Multitouch" to disable Multitouch in checkboxes there - I do encounter UI issues occasionally because of certain programs overlaying their own touch screen overlays (some 'laptop' installs types include 'optional' touch elements enabled by default for whatever reason it seems - maybe these expect it to gain popularity still) - so when you mouse click on a plugin with its own UI kit, it may create erroneous commands and get crashy.

Just posting all these because they're my boiled down choices to look at first - hoping it saves time esp. in case they are overlooked - and at least hoping it leads to a clue.

Issue apparently resolved! A poster on the Reaper forum told me to re-install PT. Until then, I thought I had the latest version, but I did not! (6.3 versus 6.3.1). Reaper even popped a message occasionally that "version 6.3 plugin has a severe bug". Installing 6.3.1 seemed to have completely cured the problem.

Is it me or Moddart never announce the update to 6.3.1 (which they say fixed an attack problem at low velocity, no mention of a plugin problem). ? Is there some kind of automatic notification that can be set?
Anyways, thanks to all who posted suggestions.

interesting find Gilles. The least I can say is that Moddart could do a better job of keeping the community informed of software updates. It would have saved me a lot of time!