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Snapshots lost in VB 6.1

Posted: 19. Dec 2019, 22:48
by RobHubi
Dear all,
after moving the PC twice I noticed that some snapshots are missing for one VM. The virtual Media Manager shows me the following Hard Disks tree:
VMMtree.jpg
VMMtree.jpg (73.77 KiB) Viewed 2002 times
With error: VERR_FILE_NOT_FOUND

Snapshot List of VM with FILE_NOT_FOUND Error:
SStree.jpg
SStree.jpg (24.39 KiB) Viewed 2002 times
What does the red stop button mean here?

However, the VM is working and I have not noticed any data loss. Nevertheless I would like to clean up the error. Is that possible? And if so, how?

My System
VirtualBox 6.1
Host: Windows 10
Guest: Windows 2012 64 bit

I look forward to tips and hints
Robert

Re: Snapshots lost in VB 6.1

Posted: 20. Dec 2019, 15:15
by scottgus1
RobHubi wrote:What does the red stop button mean here?
The red box and green arrow indicate whether the guest was running when the snapshot was taken.

Green Arrow: The snapshot was taken with the guest in a running state (a saved-state is saved into the snapshot).

Red Box: The snapshot was taken with the guest shut down (or power-off-crashed).
RobHubi wrote:after moving the PC twice I noticed that some snapshots are missing for one VM.
Hover the mouse over the missing snapshot. A pop-up will show where the missing snapshot is supposed to be:
missing snapshot hover.png
missing snapshot hover.png (100.14 KiB) Viewed 1963 times
See the red arrow in the picture. This is where your snapshot is supposed to be. You need to find that file and put it back where Virtualbox is looking for it.
RobHubi wrote:after moving the PC twice
Physically moving a computer doesn't often damage the data stored on the computer unless the move was done roughly. Or unless "moving the PC" means something different than the standard definition of "to move". Can you explain what you did?
RobHubi wrote:the VM is working and I have not noticed any data loss.
This means you are using a different snapshot than the one that requires these missing disk files. Notice that in your "VMMtree" picture, under the file starting "acd7bfc4" there are two missing files and another file starting "a0feaab5". Both "a0feaab5" and the missing file starting "2384b88a" run off "acd7bfc4". From "SStree" I see that you are running from the last snapshot. If this snapshot is running from "a0feaab5", then you aren't trying to access the missing file chain, so your guest runs fine.
RobHubi wrote:I would like to clean up the error
How to do this depends in this: How badly would you howl over the vagaries of life if you lost this whole guest? The snapshots make this possibility very possible.

Snapshots make a guest more delicate and do not work as backups. They are similar to Windows' System Restore points: they are point-in-past-time markers, not extractable, useless without the base system in place, but easier to corrupt because the files are accessible on the host drive. They do not store "files", like a backup folder would. Virtualbox snapshots store changed disk sectors, which may or may not contain the entire file. They should only be used on guests you're experimenting with and with data you wouldn't mind losing. (The forums are replete with users destroying their important data because they did something wrong with a snapshot.)

Additionally, each snapshot, if used long enough, has the potential to grow to the final size of the original drive, and will not shrink once another snapshot is taken. The guest's total data size on the host could be many times what it would have been without the snapshots, and with tremendous amounts of dead data that will never be used or changed.

Re: Snapshots lost in VB 6.1

Posted: 21. Dec 2019, 01:54
by RobHubi
I really appreciate your detailed answer, it helps me novices a lot.

I'm sorry for the confusing wording "after moving the PC twice", English is not my native language, I meant the programs have moved twice to other HW and OS.
scottgus1 wrote: ... then you aren't trying to access the missing file chain, so your guest runs fine
Ahh, I see, that's the meaning of the indentations.
Yes, your guess is correct. The current VDI file is a0feaab5 and the parent UUID is acd7bfc4. I checked it with showvdiinfo.

Thanks a lot for the clear words about snapshots, I will handle it differently in the future.

Re: Snapshots lost in VB 6.1

Posted: 21. Dec 2019, 12:53
by socratis
Read the following draft on "Snapshot basics" to get a better picture of what snapshots are, how they operate, and why it's not the greatest idea in the world to have them piling up.

If you want help fixing the problem, post the the .vbox file for the VM, by right-clicking on the VM in the VirtualBox Manager, and selecting "Show in Explorer". ZIP the selected ".vbox" file and attach it to your response.

Also, I'd need the output of the following command:
  • 
    dir /s "<Your VM's Full Path>"
where "<Your VM's Full Path>" is where you found that ".vbox" file from the previous step.

Re: Snapshots lost in VB 6.1

Posted: 28. Dec 2019, 20:16
by RobHubi
Socratis you are the most helpful person in the forum worlds!

I could solve the problem and flatten the hierarchy:
VMtree2.jpg
VMtree2.jpg (59.31 KiB) Viewed 1863 times
... and I have a backup now :-)

Many, many thanks and happy holidays
Robert

Re: Snapshots lost in VB 6.1

Posted: 22. Jun 2020, 21:26
by nbexiga
Hi @socratis
how are you?

I have the same problem... accidently i deleted snapshot files from the explorer... :(

but now i need to run the last one that i have, but appear the error that cannot load all the snapshots...

Can you kindly help me ? like you did to RobHubi ?
i would be very appreciated if you help me .
it's a very crucial machine... :)

kindly see the atached files that you requested before..

many thanks
Nuno