Storage and sharing

VM packages

A .macvisor package keeps one VM's configuration, disks, firmware/platform data, saved state, and snapshots together. Double-clicking a known package selects it in the library. Importing a foreign package gives it a new identity and MAC addresses to prevent collisions.

Disk format

MacVisor creates every disk in ASIF, Apple's sparse virtual disk format. It grows as data is written, can reclaim freed guest space, and is what linked clones and disk shrinking are built on. There is no format picker anywhere in the app.

Raw disks still work. A VM imported from another tool, or created by an older MacVisor, runs exactly as before and is labelled Raw (legacy) in VM Settings → Storage.

Converting a raw disk to ASIF

Select the stopped VM, open Settings → Storage, and use Convert to ASIF… next to the disk.

• The VM must be stopped, and must not have a suspended session or layered disk.
• A sparse raw image converts fully allocated, so conversion needs the disk's declared size in free space — a 200 GB image needs 200 GB free even if the guest only uses 40 GB. MacVisor checks first and refuses with the number rather than filling the volume.
• The converted image is validated by opening it before the configuration switches over, and the original raw file goes to the Trash.

Resizing

Storage locations

Add locations when VM data belongs on a larger internal volume, external APFS disk, or another mounted filesystem. MacVisor can create VMs in a chosen location and migrate existing bundles.

• A cold migration requires the VM to be stopped.
• A warm migration suspends a running VM, moves it, and resumes it.

Do not disconnect a storage device while its VM is running or migrating.

Storage measurements

Private size accounts for sparse files and APFS blocks shared by clones and snapshots.

Additional disks and media

Add, expand, or remove virtual disks in VM Settings while the VM is stopped. Attach ISO, raw, or other supported storage images on the configured bus. USB-bus images can be attached while supported VMs are running.

Removing a managed additional disk moves its image to the Trash, so it is recoverable until you empty it. Eject guest filesystems first and confirm the selected filename.

Shared folders

MacVisor exposes selected host folders through VirtioFS. Each folder has a guest-visible tag and can be read-only. Mount behavior inside the guest depends on its operating system and guest tools.

Shared folders deliberately cross the VM boundary. Share only the paths the guest needs, and use read-only access when possible.