Defragmenting disk files

[marius_1956]

Is there any way to defragment/compact .vdi disk files?
After using a VM for some time I suspect that the .vdi file gets fragmented all over the physical disk of my Windows host.
I would like to create a single Windows file for my .vdi file: is there any way to do it?
Regards
marius

[mpack]

After using a VM for some time I suspect that the .vdi file gets fragmented all over the physical disk of my Windows host.

You suspect or you know? Unless your host drive is nearly full I don't know why a VDI would become particularly fragmented. Size increases aren't that frequent.

Anyway it's just a normal host file, and it will benefit from a host defrag like any other file.

And I assume the VDI is on a mechanical drive, since defrag is meaningless on an SSD.

I would like to create a single Windows file for my .vdi file: is there any way to do it?

I'm afraid you have a wrong idea somewhere. A VDI is already and always a single file. Are you talking about snapshots? If yes then the question is misleading: snapshots are not created by the passage of time, they are created only when you tell VirtualBox to create a snapshot. If you don't want the snapshot anymore then just delete it. Only make sure you delete the snapshot, not revert to it, and don't delete the current state.