Failed to create a snapshot of the virtual machine => Fixed in SVN

[dfreer]

Occasionally when taking snapshots an error will occur with the following message:

Failed to create a snapshot of the virtual machine <Virtual Machine Name>

Assertion failed: [m->state == MediumState::LockedRead] at '/Users/vbox/tinderbox/4.2-mac-rel/src/VBox/Main/src-server/MediumImpl.cpp' (4069) in nsresult Medium::createDiffStorage(ComObjPtr<Medium>&, PRUint32, MediumLockList*, ComObjPtr<Progress>*, bool). Please contact the product vendor!.

Result Code: NS_ERROR_FAILURE (0x80004005) Component: Medium Interface: IMedium {29989373-b111-4654-8493-2e1176cba890}

It also appears to disconnect the virtual disk device at this point.

[Andrew]

Affecting me too. I am using vagrant and plugin to take snapshots. Very annoying. My enviorment: Ubuntu 12.04 LTS as host, Virtualbox 4.2.18, CentOS 6.4 as guest.

[Philip Boulain (SW)]

I have been able to reproduce this by taking two snapshots of a running system in a row. As long as you then shut down the VM after the assertion failure, your storage configuration is not damaged.

Fixed in this development release (thanks klaus-vb): ​http://www.virtualbox.org/download/testcase/virtualbox-4.2_4.2.19-89901~Ubuntu~precise_amd64.deb

[Frank Mehnert]

Fix is part of VBox 4.2.20.