Hi, With both the latest and stable vm I have an use case in which the vm crashed in SmalltalkImage>>garbageCollect. To set up an image that exhibits the failure , execute this with the latest pharo version: /pharo Pharo.image eval --save "{ { 'ConfigurationOfRubric'. 'Pharo'. 'Rubric' }. { 'ConfigurationOfGlamourCore'. 'Moose'. 'Glamour' }. { 'ConfigurationOfGTInspectorCore'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTPlaygroundCore'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTEventRecorder'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTSpotter'. 'Moose'. 'GToolkit' }. } do: [ :spec | Gofer new smalltalkhubUser: spec second project: spec third; package: spec first; load ]." ./pharo Pharo.image config http://www.smalltalkhub.com/mc/Pharo/Pharo50Inbox/main ConfigurationOfGToolkitCore --install=3.2 Then attempting to run the following code triggers the failure: ./pharo Pharo.image eval --save "TestRunner open model packageSearchUpdate: 'gt-tests-inspector'; classSearchUpdate: 'GTInspectorExamplesTest'; runAll" Based on the trace below the failure happens when the test GTInspectorExamplesTest calls 'Smalltalk>>garbageCollect' in the setUp method. That call can be removed, however, in other runs the failure happens in other methods calling Smalltalk>>garbageCollect. Is it possible that this is a bug with the image (some broken object) or is it a vm bug? Cheers, Andrei andrei$ ./pharo Pharo.image eval --save "{ { 'ConfigurationOfRubric'. 'Pharo'. 'Rubric' }. { 'ConfigurationOfGlamourCore'. 'Moose'. 'Glamour' }. { 'ConfigurationOfGTInspectorCore'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTPlaygroundCore'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTEventRecorder'. 'Moose'. 'GToolkit' }. { 'ConfigurationOfGTSpotter'. 'Moose'. 'GToolkit' }. } do: [ :spec | Gofer new smalltalkhubUser: spec second project: spec third; package: spec first; load ]." andrei$ ./pharo Pharo.image config http://www.smalltalkhub.com/mc/Pharo/Pharo50Inbox/main ConfigurationOfGToolkitCore --install=3.2 andrei$ ./pharo Pharo.image eval --save "TestRunner open model packageSearchUpdate: 'gt-tests-inspector'; classSearchUpdate: 'GTInspectorExamplesTest'; runAll" Segmentation fault Mon Nov 23 16:48:36 2015 https://github.com/pharo-project/pharo-vm.git Commit: 28d077d8df494ce050ca42c97c892471e8b8740c Date: 2015-10-16 12:02:43 +0200 By: Esteban Lorenzano <estebanlm@gmail.com> Jenkins build #15016 C stack backtrace: 0 Pharo 0x0004cacf reportStackState + 159 Smalltalk stack dump: 0xbffbf1a0 M SmalltalkImage>garbageCollect 0x1fd49e30: a(n) SmalltalkImage 0xbffbf1c0 I GTInspectorExamplesTest>setUp 0x2126bc80: a(n) GTInspectorExamplesTest 0x2126cb90 is not a context Most recent primitives @ basicNew @ @ @ @ @ @ @ @ @ basicNew basicNew basicNew @ @ @ @ shallowCopy new new: new: basicNew basicNew new: basicNew new: replaceFrom:to:with:startingAt: new: basicNew new: replaceFrom:to:with:startingAt: new: basicNew @ new: at:put: at:put: perform:with: perform:with: perform: @ @ basicNew @ @ @ @ @ @ basicNew @ new: at:put: at:put: perform:with: perform:with: perform: @ @ basicNew @ @ @ @ @ @ new @ @ @ @ @ basicNew @ @ new: at:put: @ @ basicNew @ @ @ @ new: at:put: at:put: at:put: at:put: new: @ at:put: @ at:put: @ at:put: @ at:put: @ @ @ @ @ @ basicNew @ @ basicNew @ @ basicNew @ @ @ @ @ shallowCopy shallowCopy @ @ new: at:put: at:put: at:put: at:put: new: @ at:put: @ at:put: @ at:put: @ at:put: @ @ @ @ @ @ basicNew @ @ basicNew @ @ basicNew @ @ @ @ @ basicNew @ @ @ @ basicNew @ @ basicNew @ @ basicNew @ @ @ @ @ basicNew @ @ @ @ basicNew @ @ perform: basicNew new: basicNew new: basicNew new: shallowCopy shallowCopy primUTCMicrosecondsClock // basicNew basicNew new: at:put: at:put: at:put: at:put: value valueNoContextSwitch basicNew new: basicNew new: new: basicNew new: replaceFrom:to:with:startingAt: primitiveGarbageCollect **IncrementalGC** **FullGC** garbageCollectMost **IncrementalGC** basicNew new: someInstance basicNew new: someInstance basicNew new: someInstance new: basicNew new: replaceFrom:to:with:startingAt: primitiveGarbageCollect **IncrementalGC** **FullGC** garbageCollectMost **IncrementalGC** wait shallowCopy shallowCopy signal wait shallowCopy shallowCopy at:put: at:put: at:put: at:put: at:put: at:put: signal wait shallowCopy shallowCopy at:put: at:put: signal new: basicNew new: replaceFrom:to:with:startingAt: primitiveGarbageCollect **IncrementalGC** **FullGC** (Segmentation fault) ./pharo: line 11: 5224 Abort trap: 6 "$DIR"/"pharo-vm/Pharo.app/Contents/MacOS/Pharo" --headless "$@"