Garageband Stuttering

Help. GarageBand playback is stuttering and is driving me mad!

I have a Macbook Pro 2015, 10.15.7 (yes, it’s old, but has run flawlessly up to now, even when playing 30+ tracks of audio and MIDI).

But today I installed the Vital synth plugin and I can’t play even one Vital MIDI track without playback stuttering and facing the ‘Error while trying to synchronise Audio and MIDI’ message.

Thanks in advance.

Martin
UK

Set the oversampling in the basic tab to 1x