Hi all,
I've found following issue.
I'm using OMV 1.0.22 with installed Virtualbox plugin.
I've just played with it by creating a shared folder on a USB stick. And it is the only non boot drive in the NAS. Then I've too USB stick out and tried to find a way to delete the shared folder. But this shared folder is still in use by the plugin and OMV doesn't give me rights to delete it. At the same time Vitrualbox plugin doesn't allows to unlock it.
I know that it looks like an issue of a plugin. Nevertheless I'd sugeest to extend plugin API and include there a option to force a unlock of shared foldes. It makes no sense to keep it because of "safity" as the folder doesn't exists (usb stick is out).