One or more virtual hard disks ... not accessible.

[bpabbott]

Running VirtualBox 3.2.8 (from Oracle) I've installed Ubuntu 10.04 as guest on a Mac OS 10.6.4 host twice. Each time everything works as expected for a several days. For the second time I am now seeing the error below.

error dialog

error_dialog.png (45.25 KiB) Viewed 4689 times

When I click (Check) I see that my Ubuntu vdi isn't accessible.

Virtual Media Manager with warning

VMM.png (52.28 KiB) Viewed 4686 times

Any suggestions?

[Sasquatch]

Did you use Spotlight or Finder to see if the file actually exists in /Users/bpabbott/Library/VirtualBox/HardDisks/? The error and Media Manager say that it doesn't. If so, then you either removed it manually or moved it to another location. Remove the entry and add it again with the new path or create a new VDI file.

[bpabbott]

Yes the vdi file is there.

$ ls -l /Users/bpabbott/Library/VirtualBox/HardDisks/*
-rw------- 1 bpabbott staff 7773299200 Oct 1 14:06 /Users/bpabbott/Library/VirtualBox/HardDisks/Ubuntu 10.vdi

Same for info via Finder ...

vdi info

vdi-info.png (18.5 KiB) Viewed 4707 times

[bpabbott]

When I try to start the Ubuntu guest (Ubuntu.vdi), I a dialog is presented that says ...

Failed to open a session for the virtual machine Ubuntu 10.

Could not open the medium
'/Users/bpabbott/Library/VirtualBox/HardDisks/Ubuntu 10.vdi'

VDI: invalid pre-header in
'/Users/bpabbott/Library/VirtualBox/HardDisks/Ubuntu 10.vdi'
(VERR_VD_VDI_INVALID_HEADER).

VD: error VERR_VD_VDI_INVALID_HEADER opening image file
'/Users/bpabbott/Library/VirtualBox/HardDisks/Ubuntu 10.vdi'
(VERR_VD_VDI_INVALID_HEADER).

[Sasquatch]

That would indicate that the VDI got corrupted. Search the forums for the error message (invalid_header) and you might get a few hits that describe how to recover the VDI. Else there is nothing to do other than start from scratch again with the VM.

[bpabbott]

I thought I'd try restoring from backup. The backups for Sept 29 and 30 din't work for me, but the one from the 27th did.