Some days ago my virtualbox vm was very slow and after many weeks of saving it, i made a shutdown.
Some days later i want to boot it and virtualbox writes me:
Now when i start virtualbox its says me, that there is a problem with a virtual disk and i can ignore and proof/validate it. when i click validate i get the gui of the "manager for virtual devices".Für die virtuelle Maschine Privater_Desktop_v2 konnte keine neue Sitzung eröffnet werden.
Could not open the medium '/home/oliver/vms/Privat/Privater_Desktop_v2/Privater_Desktop_v2-enc.vdi'.
VDI: invalid header in '/home/oliver/vms/Privat/Privater_Desktop_v2/Privater_Desktop_v2-enc.vdi' (VERR_VD_VDI_INVALID_HEADER).
VD: error VERR_VD_VDI_INVALID_HEADER opening image file '/home/oliver/vms/Privat/Privater_Desktop_v2/Privater_Desktop_v2-enc.vdi' (VERR_VD_VDI_INVALID_HEADER).
Fehlercode:NS_ERROR_FAILURE (0x80004005)
Komponente:MediumWrap
Interface:IMedium {4afe423b-43e0-e9d0-82e8-ceb307940dda}
There i see all virtual harddisk and the one with the problems.
All of them shows me size and end size, excepted the problem disk. There are only empty fields.
I opend with a hexeditor the vdi file and it looks similar like a healthy one i have tested.
i would belief, that some kind of partition table is left and i hope the files are still there.
i have a backup (~1 month old) but in the backup is a very important file missing. it has not existed at the time when i made the backup.
I read several threads here and i saw it could help if i read with dd the first blocks or a specified nr of bytes from the start of the healthy VDI file and write them to the corrupted one.
I know that a hard disk has a partition table (i think its in the mbr) and i know a filesystem has an index of the inodes and the files accociated with it. And i think then comes the files stored in the filessystem.
How can i determine how much i must read from the healty disk and write to the bad disk?
I dont know if its needed:
Linux name 4.4.0-59-generic #80-Ubuntu SMP Fri Jan 6 17:47:47 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
I hope, someone can help me.
Thanks and best regards,
Oliver