Using Henry's processToInterrupt "Look for best candidate to interrupt: - any scheduled non-finalization process of lower priority - the weak-finalization process, if scheduled - the UI process Never interrupt the idle process, since killing it is fatal" | fallback | fallback := UIManager default uiProcess. Processor scanSchedule: [:p | "suspendedContext sender == nil usually means that process is only scheduled but had no chance to run" ((p ~~ Processor backgroundProcess) and: [ p suspendedContext sender notNil]) ifTrue: [ p ~~ WeakArray runningFinalizationProcess ifTrue: [^p] ifFalse: [fallback := p]] ] startingAt: Processor activePriority. ^fallback in todays Moose 4.8 (on Pharo 20608) on the april 10 VM allows for better interruption, up to the point where the system runs out of memory without a lowspace warning after I assume trying to collect garbage for 20 minutes or so. Stephan