Hi, I got a few times the following crash while using the latest Pharo 64 bit image (Pharo64-60513) with the latest vm (pharo-mac-x86_64-201710101955-47390dc) on Mac OS. The image is around 3.5GB when the crash happens. Attached is a crash report containing the reports for three crashes. --------------------------------------------------------------------------------------------------------- Segmentation fault 0 Pharo 0x000000010ac13ad8 fixFollowedFieldofObjectwithInitialValue + 33 1 Pharo 0x000000010ac8f64e reportStackState + 884 2 Pharo 0x000000010ac8f984 sigsegv + 155 3 libsystem_platform.dylib 0x00007fff934dff1a _sigtramp + 26 4 ??? 0x0000000000000000 0x0 + 0 5 Pharo 0x000000010ac2d8a1 markAndTrace + 858 6 Pharo 0x000000010ac2a584 markObjects + 464 7 Pharo 0x000000010ac29d6c fullGC + 72 8 Pharo 0x000000010ac49df8 primitiveFullGC + 45 9 Pharo 0x000000010ac09445 interpret + 26715 10 Pharo 0x000000010ac13816 enterSmalltalkExecutiveImplementation + 152 11 Pharo 0x000000010ac02e8c interpret + 674 12 Pharo 0x000000010ac90cd1 -[sqSqueakMainApplication runSqueak] + 394 13 Foundation 0x00007fff8ecb0641 __NSFirePerformWithOrder + 326 14 CoreFoundation 0x00007fff87892127 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 23 15 CoreFoundation 0x00007fff87892080 __CFRunLoopDoObservers + 368 16 CoreFoundation 0x00007fff87884188 __CFRunLoopRun + 872 17 CoreFoundation 0x00007fff87883bd8 CFRunLoopRunSpecific + 296 18 HIToolbox 0x00007fff88ffd56f RunCurrentEventLoopInMode + 235 19 HIToolbox 0x00007fff88ffd1ee ReceiveNextEventCommon + 179 20 HIToolbox 0x00007fff88ffd12b _BlockUntilNextEventMatchingListInModeWithFilter + 71 21 AppKit 0x00007fff8d56c8ab _DPSNextEvent + 978 22 AppKit 0x00007fff8d56be58 -[NSApplication nextEventMatchingMask:untilDate:inMode:dequeue:] + 346 23 AppKit 0x00007fff8d561af3 -[NSApplication run] + 594 24 AppKit 0x00007fff8d4de244 NSApplicationMain + 1832 25 libdyld.dylib 0x00007fff8ea3a5c9 start + 1 Smalltalk stack dump: 0x7fff54ff9fb0 I SmalltalkImage>garbageCollect 0x11317f1c8: a(n) SmalltalkImage 0x7fff54ff9ff8 I Array class(Behavior)>handleFailingBasicNew: 0x112d62738: a(n) Array class 0x7fff54ffa038 M Array class(Behavior)>basicNew: 0x112d62738: a(n) Array class 0x7fff54ffa070 M Array class>new: 0x112d62738: a(n) Array class 0x7fff54ffa0b0 M OrderedCollection>growAtLast 0x11235e740: a(n) OrderedCollection 0x7fff54fe4948 M OrderedCollection>makeRoomAtLast 0x11235e740: a(n) OrderedCollection 0x7fff54fe4978 M OrderedCollection>addLast: 0x11235e740: a(n) OrderedCollection 0x7fff54fe49b0 M [] in OrderedCollection>addAllLast: 0x11235e740: a(n) OrderedCollection 0x7fff54fe49f8 M OrderedCollection>do: 0x176a416e8: a(n) OrderedCollection ... --------------------------------------------------------------------------------------------------------- Cheers, Andrei