Parent VDI is missing

[Plater]

Very strange problem, but here is what happened:

Have been using a "Data" vdi for quite some time, the size is 45GB. There is no operating system installed, it is just a vdi I attach to a vbox when needed.
Now for some unknown reason, this Data vdi had a parent that was an EMPTY vdi (104KB). I never knew this before, so I also never made any backup of this vdi and when cleaning up my folders, I deleted it (!).

That is where the problems started of course and I got the error: "cannot find the parent UUID.." and then I found out that empty vdi must have been the parent. I still have not found any easy way to re-create this situation by the way.

So I cannot attach my Data vdi anymore and this is a big problem, so here are the things I already tried:
1) with hex editor I removed the parent UUID reference in the Data vdi, but then it complained it could not find {00000000-00...} uuid, so that did not solve much.
So then I created a clone of the Data vdi with CloneVDI 2.10, the clone was successfully made, but when I attach it, it gives an unallocated drive.
2) i made an empty vdi, took the uuid of this empty vdi and then with hex editor had the Data vdi point to this newly created empty hdd, but although I could attach the hdd now, it was unallocated.

When looking at the VDI Header information (using CloneVDI), i see that there is a UUID (parent) and also a UUID (pmodify), i don't know if this is important and how.

All I want is to attach my Data vdi again ! Unfortunately there is no way I can get back the empty parent vdi, but it was an empty file, which was there for a reason unclear to me, but because of that gives me all these problems

Hope really anyone can help and I can give more information if needed, just ask.

Thanks

[mpack]

Are you using snapshots in the VM at all? If yes then when you take a snapshot it preserves the state of all drives currently connected to the VM, not just the state of the primary disk.

What I think you did was create a snapshot soon after installing your guest OS. At that time the data VDI would have been formatted, a filesystem was put on it, but no other data. Your offshoot child VDI therefore would not include the filesystem, just file data. You need both to make a complete disk image.

If this scenario is correct then you should have found your base "Data.VDI", empty unless you been moving it around to other VMs, plus a snapshot VDI {0123.abcd.who.knows}.vdi, which refers to data.vdi as the parent. The snapshot has data written to the drive by this VM.

Deleting the base VDI in a snapshot chain is a terminal error. The only known cure is recovering from a backup. If I was desperate I might try retracting my steps, doing exactly what I did (in particular the disk size must be identical to before) to create that first blank base VDI, then hack the UUID chain of the child to refer to this replacement base.