MacVisor GA

Known limitations

What MacVisor 27 doesn't do, or does only in part, in one place, with a link to the details of each.

MacVisor is built on Apple's Virtualization framework, and some of its limits are the framework's. This page collects them, with links to the details.

The Mac and the platform

  • Apple Silicon and macOS 27 only. There is no Intel version, and MacVisor doesn't emulate x86, so x86 guests don't boot. See System requirements.
  • Two macOS VMs at a time per Mac, a limit of Apple's license and framework.
  • A Linux guest that ignores the power button shuts down from MacVisor only through the MacVisor Agent. Without the agent (appliances, VMs installed from an ISO), enable acpid in the guest or use Power Off.
  • Four network interfaces per VM, and 32 across the Mac. A VM that would go past either doesn't start. See VM settings.
  • VMs run while their user is logged in. The background service runs per user. An unattended Mac needs automatic login, and FileVault stops an unattended reboot at its unlock screen. See Always-on host.
  • A sleeping Mac freezes its VMs. Keep a host awake in its energy settings. See Always-on host.
  • One user at a time. MacVisor is developed and tested on Macs with one user signing in. With several accounts logged in at once, <vm>.mvz names resolve only for the first account's VMs. See Names.

Saved sessions

  • Suspended VMs and live snapshots restore only on the macOS release and the MacVisor version that saved them, and only while you are logged in at the Mac with the screen unlocked. Shut VMs down before you update either. See Updates.
  • Disks set to Cached sometimes fail to resume or to restore a live snapshot on macOS 27. See VM settings.

Display, devices and storage

  • No GPU acceleration for Linux and Windows guests. Only macOS guests get Apple's accelerated graphics. See Windows 11 guests.
  • One display per VM. Additional displays aren't supported.
  • USB audio devices can't be passed through, nor any other device with isochronous endpoints. See Sound.
  • NVRAM can't be edited on macOS 27: the interface MacVisor relies on is unavailable there.
  • Only ASIF disks shrink, and only a macOS guest's. Linked clones need ASIF too. See Resizing.
  • On a network share or a drive that isn't APFS, every clone, snapshot and revert copies the disks in full, and a VM can't be moved to the Trash from a network share. See Storage locations.

Networking

  • The firewall filters IPv4 only. A firewalled network drops IPv6, and traffic between two VMs on the same network never reaches the firewall. See Network firewall.
  • macOS chooses a shared network's subnet. A fixed subnet works only for host-only networks, and on macOS 27.2 VMs on one get no network link. See Addressing.
  • macOS can stop a custom network under its VMs when a VM on Apple's NAT quits. Its VMs are off the network for about a minute, until MacVisor makes it again. See When macOS stops a network.
  • An update's network changes finish only once every VM on a custom network has been stopped and started again. See After an update.
  • Network-level port forwards can't change while any VM uses the network.
  • At logout or restart, guests get 30 seconds to shut down before they are powered off, unless VMs are set to suspend. See When you log out or restart the Mac.

Guests

  • Windows 11 (Tech Preview): no TPM or Secure Boot, no GPU acceleration, no memory balloon, nested virtualization or Rosetta, and sound in the VM's own window only with a test-signed driver. See Windows 11 guests.
  • FreeBSD (experimental): SSH only, with no screen or console after the loader, and no agent, shared folders or container runtimes. See FreeBSD.
  • Appliances (made without cloud-init) have no MacVisor account or agent, so mvz shell and exec refuse them, and a FreeBSD-based one can't be shut down from MacVisor. See Appliances.
  • Ubuntu Desktop gets the clipboard only when sharing is Both Ways, the default, and then gets everything you copy on the Mac, passwords included. See Ubuntu Desktop.
  • AI sandboxes (Tech Preview): at most two macOS sandboxes, no Neural Engine and only part of the GPU in a VM, and no Windows sandboxes. The gateway refuses the providers' own internet tools that MacVisor knows of, so one a provider adds later may get through. See AI sandboxes and Cloud models.
  • AI agents over MCP (Tech Preview): for agents on the same Mac only (no network endpoint). Commands and files reach cloud-image Linux and macOS VMs; Windows VMs get the screen and input only, and appliances and ISO-installed Linux VMs neither. Screenshots and input need a VM that isn't headless. See AI agents and MCP.
  • The guest agent doesn't offer every feature everywhere: Windows has no Docker socket or pre-snapshot flush, and FreeBSD has no agent at all. See Guest tools.

The app, the CLI and moving in

  • A few features are app-only: converting a raw disk to ASIF, shrinking a disk, network-level port forwards, VLAN interfaces, per-network DHCP, DNS, NAT and RA switches, empty VMs for an ISO install, Ubuntu Desktop in a new VM, USB passthrough and adding storage locations. See App-only features.
  • Report a Problem is in the app only. On a Mac you reach over SSH, collect the logs by hand. See On a Mac you reach only over SSH.
  • VMs from other apps aren't imported. Linux disks come across with mvz create <disk>; macOS and Windows VMs are made again. See Bring VMs from other apps.
  • The mvz CLI and the logs are in English, whatever the app's language.