What causes "field `mountType` must be %#q or %#q for VZ driver , got %#q" in lima-vm/lima?

Set mountType to "virtiofs" or "reverse-sshfs" in the instance YAML

field `mountType` must be %#q or %#q for VZ driver , got %#q

Error message

field `mountType` must be %#q or %#q for VZ driver , got %#q

What it means

Validation error from the VZ driver: the instance's `mountType` is neither of the two values allowed for VZ (typically "virtiofs" or "reverse-sshfs", printed via %#q). Other mount types (e.g. 9p) are unsupported with Virtualization.framework.

Source

Thrown at pkg/driver/vz/vz_driver_darwin.go:277

func validateConfig(cfg *limatype.LimaYAML) error {
	if cfg == nil {
		return errors.New("configuration is nil")
	}
	macOSProductVersion, err := osutil.ProductVersion()
	if err != nil {
		return err
	}
	if macOSProductVersion.LessThan(*semver.New("13.0.0")) {
		return errors.New("VZ driver requires macOS 13 or higher to run")
	}
	if runtime.GOARCH == "amd64" && macOSProductVersion.LessThan(*semver.New("15.5.0")) {
		logrus.Warnf("vmType %s: On Intel Mac, macOS 15.5 or later is required to run Linux 6.12 or later. "+
			"Update macOS, or change vmType to `qemu` if the VM does not start up. (https://github.com/lima-vm/lima/issues/3334)",
			*cfg.VMType)
	}
	if cfg.MountType != nil && *cfg.MountType == limatype.NINEP {
		return fmt.Errorf("field `mountType` must be %#q or %#q for VZ driver , got %#q", limatype.REVSSHFS, limatype.VIRTIOFS, *cfg.MountType)
	}
	if cfg.TPM != nil && *cfg.TPM {
		return errors.New("field `tpm` is not supported on VZ driver")
	}
	if cfg.OS != nil && *cfg.OS == limatype.WINDOWS {
		return errors.New("currently Windows guest OS is only supported on QEMU")
	}
	if *cfg.Firmware.LegacyBIOS {
		logrus.Warnf("vmType %s: ignoring `firmware.legacyBIOS`", *cfg.VMType)
	}
	for _, f := range cfg.Firmware.Images {
		switch f.VMType {
		case "", limatype.VZ:
			if f.Arch == *cfg.Arch {
				return errors.New("`firmware.images` configuration is not supported for VZ driver")
			}
		}
	}

View on GitHub (pinned to dd909d0973)

Solutions

Set mountType to "virtiofs" or "reverse-sshfs" in the instance YAML
Use the QEMU driver if 9p mounts are required

Example fix

// before (lima.yaml)
vmType: vz
mountType: 9p
// after
vmType: vz
mountType: virtiofs

Defensive patterns

Strategy: validation

Validate before calling

if vmType == "vz" && mountType == "9p" {
    mountType = "virtiofs" // pre-correct before starting
}

Try / catch

if err := start(); err != nil && strings.Contains(err.Error(), "field `mountType`") {
    // change mountType to virtiofs and retry
}

Prevention

Use virtiofs with the VZ driver
Run `limactl validate` before starting
Keep per-driver config profiles instead of copying QEMU configs

When it happens

Trigger: Config sets mountType: "9p" (or limatype.NINEP) while vmType is "vz".

Common situations: Copying a QEMU-instance config that used 9p mounts to a VZ instance; explicitly choosing 9p for QEMU performance reasons and switching drivers without updating the field.

Related errors

AI-assisted analysis of lima-vm/lima@dd909d0973 (2026-09-01). Data as JSON: /api/errors/b09301a75b79fada. Report an issue: GitHub.