Suddenly unable to start a VM

[Kurisu]

After a very unexpected system crash, of which no reasons have yet to be found and where VirtualBox was not running beforehand, I am unable to start any of my VMs.
I have two VMs that I use, a Windows 7 and a Windows 10. Both were running fine before the crash, now both give the following error, with different vdi files of course, when I try to start them.

Code: Select all

Failed to open a session for the virtual machine Windows.

Could not open the medium '/home/woelkers/space/VirtualBox-Disks/Windows.vdi'.

VD: error VERR_ACCESS_DENIED opening image file '/home/woelkers/space/VirtualBox-Disks/Windows.vdi' (VERR_ACCESS_DENIED).

Result Code: NS_ERROR_FAILURE (0x80004005)
Component: MediumWrap
Interface: IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}

The obvious thing to check is that the vdi files and directories have the proper permissions. They both have permissions of 600, with my username set as owner. No ACL is set. The directories that contain the files are the same.
I did try to change the directory and file permissions to 666, this changed nothing.

Next I tried removing one of the vdi files, for my Windows 10 VM, from the Virtual Media Manager and attempted to add it back to the VM. This gave the following similar error, note the difference in the Result Code.

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Failed to open the disk image file /home/woelkers/VirtualBox VMs/Windows 10/Windows 10.vdi.

Permission problem accessing the file for the medium '/home/woelkers/VirtualBox VMs/Windows 10/Windows 10.vdi' (VERR_ACCESS_DENIED).

Result Code: VBOX_E_FILE_ERROR (0x80BB0004)
Component: MediumWrap
Interface: IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}
Callee: IVirtualBox {0169423f-46b4-cde9-91af-1e9d5b6cd945}
Callee RC: VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)

These two files are on different hard drives so I ran an fsck on both while they were unmounted. Neither came up with any errors.

I have seen similar errors posted but nothing exactly like mine and none of the suggestions in those other posts, blogs, or forums has helped. Perhaps someone here can assist.

[socratis]

After a very unexpected system crash ... VirtualBox was not running ... '/home/woelkers/space/VirtualBox-Disks/Windows.vdi' ... ACCESS_DENIED

I'd say that something is wrong with your filesystem. And its permissions. If I'm not mistaken (could be), you should have at least RX access to the whole path, not just to the end file. That means all the directories that you got to travel through. Make sure that it's indeed the case.

I'm afraid that's all I have...