I can’t find a repeatable way of getting Audacity to crash , but breaking the VST-preview is 100% repeatable for me … To break the preview a particular VST-effect the steps are …
Open 1 track in Audacity, select part of it.
Preview VST-effect , apply VST-effect, uncheck “enable” tickbox on VST-effect, but don’t close VST-effect.
[ previewing not necessary to cause fault , it’s just included here to show preview works at this stage ].
Playback the part of track #1 where VST-effect has been applied. [ this playback seems essential to cause the fault ].
Open a new track in another instance of Audacity , NB: VST-effect is still open in instance #1.
Close the VST-effect ( which is in instance #1 ).
Open the same VST-effect in instance #2 , you’ll now find preview isn’t rendered in track #2 , (preview broken).
Close VST-effect ( which is in instance #2 ).
Re-Open same VST-effect in instance #1 , preview is now not rendered in track #1 either, where it had worked previously.
To recover the preview of that particular VST-effect it is necessary to close all instances of Audacity.
If you close the VST-effect in instance #1 before opening a new instance of Audacity , VST-effect preview works OK in instance #2. Moral of the story : close all VST-effects before opening a new instance of Audacity.
********************** [ “instance of Audacity” = “new Audacity window” ] **********************
[ In my case the above formula will break the preview in the folowing VST-effects :
SpitFish, Antress Modern DeEsser , Anwida DX reverb light, Acon Multiply , DBlue Glitch , DtBlkFx ].