"No bootable medium found" after VDI resized (Win 7 on Ubuntu 14.04.4)

[seanos]

I’ve read through a lot of threads where people had similar problems after resizing, but I’ve found nothing helpful so far. First off…

1. this is a standard VDI (not a VHD)
2. there are no snapshots
3. I followed the How to resize a Virtual Drive FAQ (I can’t post URLs)

The disk is pretty full (hence the resize) — could this be part of the problem?

I also tried compacting in case that made a difference.

/media/vm/VirtualBox VMs/Windows 7 64 bit$ VBoxManage showmediuminfo Windows\ 7\ 64\ bit.vdi 
UUID:           ff2a905d-5234-4a4c-ae41-8459fe8b0818
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /media/vm/VirtualBox VMs/Windows 7 64 bit/Windows 7 64 bit.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       25600 MBytes
Size on disk:   25520 MBytes
Encryption:     disabled
In use by VMs:  Windows 7 64 bit (UUID: 77b93170-602e-407f-8b39-06575acbc0b1)
/media/vm/VirtualBox VMs/Windows 7 64 bit$ VBoxManage modifymedium Windows\ 7\ 64\ bit.vdi --compact
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
/media/vm/VirtualBox VMs/Windows 7 64 bit$ VBoxManage showmediuminfo Windows\ 7\ 64\ bit.vdi 
UUID:           ff2a905d-5234-4a4c-ae41-8459fe8b0818
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /media/vm/VirtualBox VMs/Windows 7 64 bit/Windows 7 64 bit.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       25600 MBytes
Size on disk:   25488 MBytes
Encryption:     disabled
In use by VMs:  Windows 7 64 bit (UUID: 77b93170-602e-407f-8b39-06575acbc0b1)
/media/vm/VirtualBox VMs/Windows 7 64 bit$ VBoxManage modifymedium Windows\ 7\ 64\ bit.vdi --resize 51200
0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
/media/vm/VirtualBox VMs/Windows 7 64 bit$ VBoxManage showmediuminfo Windows\ 7\ 64\ bit.vdi 
UUID:           ff2a905d-5234-4a4c-ae41-8459fe8b0818
Parent UUID:    base
State:          created
Type:           normal (base)
Location:       /media/vm/VirtualBox VMs/Windows 7 64 bit/Windows 7 64 bit.vdi
Storage format: VDI
Format variant: dynamic default
Capacity:       51200 MBytes
Size on disk:   25488 MBytes
Encryption:     disabled
In use by VMs:  Windows 7 64 bit (UUID: 77b93170-602e-407f-8b39-06575acbc0b1)

If I attach a live Ubuntu ISO and look at the VDI with GParted it just shows as all unallocated space.

Is there something I’m missing?

Edit: VirtualBox 5.0.26 r108824

[mpack]

Do you have a backup of the VDI from before you modified it?

Btw, no: the fact that your 25GB VDI was nearly full should have made no difference. There have been bugs related to size before, but those kick in at the 256GB mark. 25GB is nothing.

And you are certain that the disk you are using in the VM is not a clone made before the resize?

[seanos]

Do you have a backup of the VDI from before you modified it?

Btw, no: the fact that your 25GB VDI was nearly full should have made no difference. There have been bugs related to size before, but those kick in at the 256GB mark. 25GB is nothing.

And you are certain that the disk you are using in the VM is not a clone made before the resize?

I do have a backup (more than one in fact). It is possible that it was a cloned at some point. In any case I have just managed to get it to work…

1. copied the VDI using the GUI
2. attached the new VDI
3. Win 7 showed the drive as offline (due to a ‘signature collision’ though it has a new UUID)
4. booted Ubuntu & resized the partition
5. shuffled the boot order & booted the copy
6. Windows ran a chkdsk

It seems to work now, but maybe this has invalidated the copy of Windows. <sigh>

[mpack]

It seems to work now, but maybe this has invalidated the copy of Windows. <sigh>

Cloning the disk usually doesn't invalidate Win7. Cloning the VM is a different story, since Win7 considers that a new motherboard. If you know how to juggle VM UUIDs then this is fixable, or you can just reactivate with the new motherboard.