Virtual Box refuses to boot – “The device helper structure version has changed.”

You will receive this error when you have a version mismatch between Virtual Box and the virtualbox-ext-pack version. This can be caused by an automatic update. The solution is applied in the host system and is very simple. Especially on Linux systems such as Ubuntu, since here the dependencies are automatically matched to the correct version. For Windows users this means to get the current Virtual Box Version ( Help -> About Virtual Box). And then manually installing the correct version of the virtualbox-ext-pack.

On Ubuntu however, it is sufficient to execute the following command:

Thats it. Your versions should be aligned again and you are able to boot the virtual machine.