What causes "field `disk` has an invalid value: %w" in lima-vm/lima?

Fix the `disk:` value in lima.yaml to a valid size string such as `50GiB` or `100GB` (no space between number and unit)

field `disk` has an invalid value: %w

Error message

field `disk` has an invalid value: %w

What it means

Lima validates the `disk` field of LimaYAML during Validate(). The value must be a size string parseable by kballard/go-units RAMInBytes (e.g. "50GiB", "100G"). If parsing fails, this error is joined into the accumulated validation errors with the underlying parse error via %w.

Source

Thrown at pkg/limayaml/validate.go:115

			if err != nil {
				errs = errors.Join(errs, err)
			}
			if f.Initrd.Arch != f.Arch {
				errs = errors.Join(errs, fmt.Errorf("images[%d].initrd has unexpected architecture %#q, must be %#q", i, f.Initrd.Arch, f.Arch))
			}
		}
	}

	if *y.CPUs == 0 {
		errs = errors.Join(errs, errors.New("field `cpus` must be set"))
	}

	if _, err := units.RAMInBytes(*y.Memory); err != nil {
		errs = errors.Join(errs, fmt.Errorf("field `memory` has an invalid value: %w", err))
	}

	if _, err := units.RAMInBytes(*y.Disk); err != nil {
		errs = errors.Join(errs, fmt.Errorf("field `disk` has an invalid value: %w", err))
	}

	for i, disk := range y.AdditionalDisks {
		if err := identifiers.Validate(disk.Name); err != nil {
			errs = errors.Join(errs, fmt.Errorf("field `additionalDisks[%d].name is invalid`: %w", i, err))
		}
	}

	for i, f := range y.Mounts {
		if !filepath.IsAbs(f.Location) && !strings.HasPrefix(f.Location, "~") {
			errs = errors.Join(errs, fmt.Errorf("field `mounts[%d].location` must be an absolute path, got %#q",
				i, f.Location))
		}
		// f.Location has already been expanded in FillDefaults(), but that function cannot return errors.
		loc, err := localpathutil.Expand(f.Location)
		if err != nil {
			errs = errors.Join(errs, fmt.Errorf("field `mounts[%d].location` refers to an unexpandable path: %#q: %w", i, f.Location, err))
		}

View on GitHub (pinned to dd909d0973)

Solutions

Fix the `disk:` value in lima.yaml to a valid size string such as `50GiB` or `100GB` (no space between number and unit)
If set via CLI, quote/reformat the --set expression, e.g. `limactl edit --set 'disk: 60GiB' inst`
Run `limactl template validate` on the file to confirm the fix before starting

Example fix

// before
disk: 50 GB
// after
disk: 50GiB

Defensive patterns

Strategy: validation

Validate before calling

const sizeRe = /^\d+(\.\d+)?(KiB|MiB|GiB|TiB|kB|MB|GB|TB|B|K|M|G|T)?$/i
function validDiskSize(v) { return typeof v === 'string' && sizeRe.test(v.trim()) && !/\s/.test(v) }
// call before: validDiskSize(cfg.disk)

Type guard

function isDiskSize(v) { return typeof v === 'string' && /^\d+(KiB|MiB|GiB|TiB|KB|MB|GB|TB|B)?$/i.test(v) }

Try / catch

try { await limactl(['template','validate', file]) } catch (e) { if (/field `disk` has an invalid value/.test(e.message)) { fixDiskField(); } else throw e }

Prevention

Always attach units with no whitespace: 50GiB not "50 GB"
Run `limactl template validate` after every manual edit
Use `limactl edit --set` with tested values rather than free-text YAML edits

When it happens

Trigger: Calling limactl create/start/edit/restart/template validate/apply with a lima.yaml whose `disk:` value is not a valid byte-size string, e.g. `disk: 50 GB` (space), `disk: 50gb` variants unsupported by the parser, or a bare number with no unit.

Common situations: Hand-editing lima.yaml or using `limactl edit --set 'disk: 50 GB'`; copy-pasting sizes from docs of other tools; typos like `disk: 50Gi` vs `50GiB` depending on parser support.

Related errors

AI-assisted analysis of lima-vm/lima@dd909d0973 (2026-09-01). Data as JSON: /api/errors/534187d796e770f8. Report an issue: GitHub.