The short answer
No. Your data. Shrink it from its app; don’t delete the folder.
What is it?
VirtualBox keeps each virtual machine in its own folder in ~/VirtualBox VMs, with its .vbox settings file, .vdi or .vmdk disks, snapshots and logs. Each holds a complete guest system with your files. Typically 10–100 GB per VM.
Whole computers with your files inside. Offload to an external drive; never deleted automatically.
What happens if you delete it?
No. A deleted VM and its files are gone unless you have exported or backed it up.
How to remove it properly
In VirtualBox, select a VM you no longer need and choose Machine › Remove › Delete all files. For VMs you keep, delete old snapshots; a dynamically allocated VDI can be compacted with VBoxManage modifymedium disk <file.vdi> --compact after zeroing free space inside the guest.
Better moved to an external drive than deleted.
Before you delete it
Copy out your files before removing a VM, and check it is not used by a tool such as Vagrant.
How MoreRoom helps
MoreRoom recognises this as your data and never suggests deleting it. It shows how much space it takes, so you can shrink it from its own app.
Frequently asked questions
Can I delete VirtualBox VMs in the VirtualBox VMs folder?
No. Your data. Shrink it from its app; don’t delete the folder. No. A deleted VM and its files are gone unless you have exported or backed it up.
Will VirtualBox virtual machines come back after I delete it?
No. No. A deleted VM and its files are gone unless you have exported or backed it up.
How do I remove VirtualBox virtual machines properly?
In VirtualBox, select a VM you no longer need and choose Machine › Remove › Delete all files. For VMs you keep, delete old snapshots; a dynamically allocated VDI can be compacted with VBoxManage modifymedium disk <file.vdi> --compact after zeroing free space inside the guest.