*I have copied the below issue from https://github.com/hpi-swa/smalltalkCI/issues/366.*

Hi!

Time to time, the Pharo VM crashes, without any apparent reasons. For example, in https://travis-ci.org/ObjectProfile/Roassal2/jobs/365943067 ``` VM: 201708271955 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $ Date: Sun Aug 27 21:55:26 2017 +0200 $ Plugins: 201708271955 https://github.com/OpenSmalltalk/opensmalltalk-vm.git $ C stack backtrace & registers: eax 0x1e750080 ebx 0x00000100 ecx 0x00000020 edx 0x00000002 edi 0x00000020 esi 0x00000020 ebp 0xbff09c58 esp 0xbff09c58 eip 0x000e848d 0 Pharo 0x000e848d fetchByteofObject + 9 1 Pharo 0x00149400 reportStackState + 819 2 Pharo 0x001497a2 sigsegv + 191 3 libsystem_platform.dylib 0xa1742e5b _sigtramp + 43 ```

And a bit below: ``` Smalltalk Smalltalk stack dump: 0xbff11ce8 I SessionManager>snapshot:andQuit: 0x6b496a8: a(n) SessionManager 0xbff11d18 I [] in SmalltalkImage>snapshot:andQuit: 0x5517fa0: a(n) SmalltalkImage 0xbff11d3c I CurrentExecutionEnvironment class>activate:for: 0x5af3520: a(n) CurrentExecutionEnvironment class 0xbff11d64 I DefaultExecutionEnvironment(ExecutionEnvironment)>beActiveDuring: 0x5e2bc70: a(n) DefaultExecutionEnvironment 0xbff11d88 I DefaultExecutionEnvironment class>beActiveDuring: 0x5b1d8a8: a(n) DefaultExecutionEnvironment class 0xbff11dac I SmalltalkImage>snapshot:andQuit: 0x5517fa0: a(n) SmalltalkImage ```

It seems to happens randomly

/cc @bergel