Argthtjtr

My host is WinXP SP3, and I have 2 VMs, one Ubuntu and the other WinXP SP2. Everything was shut down last night when I went to bed. This morning, the WinXP VM was showing inaccessible. Everything is greyed out except for the refresh button that does nothing. No access to 'Settings' or anything else. How to I get it back instead of creating another one. The VDI file is still there.

Worse comes to worst, locate the VDI file that represents your virtual hard disk, and create a new VM using that as your hard drive. You'll lose any snapshots, of course.

The default directory for VDI files is c:documents and settungs\application data.virtualboxHardDisks, I believe. (I use a Linux host and don't currently have a Windows-hosting box to check.)

This has worked for me in many occassions:

1. Pay attention to the error as to why it is inaccessible (sort of "can't find uuid={e973ec45-4137-4120-8052-ccb641c8f5e6}")




2. Locate the .vbox file in your VM folder (right click --> Show in Explorer)




3. Edit this file (e.g.: VIRTUAL1.vbox) using Wordpad (don't use NOTEPAD for this, as it won't handle the UNIX style lines in a proper manner!)




4. Close VirtualBox



5. 
   

   Within the opened file, locate the reference to the complex string (e.g. {e973ec45-4137-4120-8052-ccb641c8f5e6}) reported in 1., it'll usually be between delimiters such as these:

   
   
   

   <AttachedDevice type="HardDisk" port="1" device="0">
   
     <Image uuid="{e973ec45-4137-4120-8052-ccb641c8f5e6}"/>
   
   </AttachedDevice>
   
   

   
   



6. Delete the whole 3 lines above (just save a copy of the unmodified file first) and save the file. What you've done here is delete a reference to a snapshot which is the cause of the trouble.




7. Open VirtualBox again; your Inaccessible VM should now be accessible.

the information is stored in XML files, are they still there?

check c:documents and settungs<user>application data.virtualboxmachines

did you receive an automatic update? sometimes new versions render old virtual machines useless, in this case uninstall virtualbox, reinstall the older version and disable automatic update.

older versions can be obtained from FileHippo.com

It happened to me to day, I shutdown a guest operating system, and the virtual box manager told be that it was not accessible.

Luckily I just closed the manager and restarted it and all was well.

A broken solution:

Call me old fashioned but should software should work - in this case by supporting backwards compatibility?

Shutting down virtualbox, copying the xxx.xml file to xxx.xbox,
adding the xxx.vdi file through the Virtual media manager, in file browser double click xxx.vbox file to register vm.

This works till a point where the VM's created this way work and suddenly become inaccessible.

I did delete the add new network adapters, which are directly associated with the machine and not the VM.

For VirtualBox v5.2.24 on Mac OS X (possibly on other systems and versions) there is a command line tool:

vbox-img

That has a repair option:

vbox-img repair --filename <file_name>

I would suggest giving this a try on VDI files (VirtualBox preferred) before venturing to manually editting application files.