Thanks for your replies, guys. In answer to your questions (and I should have included these stats originally – sorry ☹):-
PC is old (2012 Chillblast custom build Music Production PC) but still runs well, especially after the SSD and RAM upgrades.
Processor: Intel(R) Core(TM) i5-3570K CPU @ 3.40GHz 3.40 GHz (Quad core)
RAM: 16GB
System: Windows 10 Home 64-bit, x64 based processor
PowerTracks 22 - Build 3
System Disc – 1TB SSD
Data Disc – 2TB SSD
Focusrite USB ASIO
VST – PG Music Coyote WT/ DXi/VSTi
I sometimes use a limited number of SF2’s via Coolsoft Virtual Synth, but not when I want to render the tracks to WAV.

I don’t understand what you mean by vi resources. I haven’t used any additional plugins if that’s what you mean, only the virtual synth.

I’m currently using the supplied USB cable for the Focusrite.

I rendered the piano track containing CC64 events and the CPU load went up to 99.7%. I then rendered another piano track with no CC64 events and, again, the CPU load was 99.7%.

I can’t find a log reporting the error. I have checked CPU temperatures and they seem to be fine. I did notice that only core#1 load went to maximum.

One problem solved though. Part of the cause for instrument dropout was that I was using Windows Media Player 32-bit for playback. This also started up WUDFHost, which together used up all CPU capacity even before it started to play the file. I switched to Groove Music player and it sounded much better with minimal dropout. Looks like a combase.dll problem, which I can try to fix, although I’ll stay with Groove Player.

PowerTracks Pro Audio 2022, Sibelius Ultimate, Ableton Live 11 Suite, BIAB 2023, RealBand 2023, CoolSoft Virtual Synth, Focusrite 4i4 3rd generation, Audacity, NVIDIA GeForce GT520,