VBoxSVC crashes when restoring old snapshot.

[jguerrero]

This guest was imported into 4.1.0 from a prior version. I had created about 4 snapshots and then deleted one of the
older ones (not sure of the order here though). Then I started up the guest, did some work and decided to go back to
an older snapshot. I powered off the VM and unchecked the option to create a new snapshot. I then highlighted the
oldest snapshot and clicked the button to restore it. Apparently, VBoxSVC crashed and the GUI displayed my guest as
inaccessible. Thankfully, I was able to exit VirtualBox and restart it and find that the guest was once again accessible.

Unfortunately, I did not open this ticket soon enough. I do not see a guest log that is old enough to cover the time period
of the crash. I will upload the oldest one which at least shows some of the "then current state" (I am still on the same
"snapshot chain"). I will also upload the MacOSX crash report.

I also have another MacOSX crash report from 4.0.12 where I was also trying to restore an old snapshot. Please advise
if that would be interesting for you and I will upload it, too.

Thanks

PS: here is the stack trace of the offending thread, in case it is easier for the ticket search engine to index this ticket for

someone else's search.

Thread 14 Crashed:
0   VBoxSVC                       	0x000dd73b std::list<ComObjPtr<MediumAttachment>, std::allocator<ComObjPtr<MediumAttachment> > >::remove(ComObjPtr<MediumAttachment> const&) + 11
1   VBoxSVC                       	0x001594d6 SessionMachine::restoreSnapshotHandler(SessionMachine::RestoreSnapshotTask&) + 1158
2   VBoxSVC                       	0x0015c238 SessionMachine::RestoreSnapshotTask::handler() + 24
3   VBoxSVC                       	0x00150c48 SessionMachine::taskHandler(RTTHREADINT*, void*) + 40
4   VBoxRT.dylib                  	0x003e6fe0 rtThreadMain + 64
5   VBoxRT.dylib                  	0x00439d8e rtThreadNativeMain(void*) + 142
6   libSystem.B.dylib             	0x9a811259 _pthread_start + 345
7   libSystem.B.dylib             	0x9a8110de thread_start + 34

[jguerrero]

Oldest log file for the crashed guest.