What causes "Error, malformed registry path: '%s'" in JanDeDobbeleer/oh-my-posh?

Include the full path with backslashes, e.g. "HKLM\Software\Microsoft\Windows NT\CurrentVersion\EditionID".

Error, malformed registry path: '%s'

Error message

Error, malformed registry path: '%s'

What it means

WindowsRegistryKeyValue parses an input string of the form "ROOT\Path\Key" (or "ROOT\Path\" for the Default value). strings.Cut on the first backslash must produce both a root key and a remainder; if the input contains no backslash at all, the path is malformed and the function returns this error instead of querying the registry.

Source

Thrown at src/runtime/terminal_windows.go:141

// If the path ends in "\", the "(Default)" key in that path is retrieved.
func (term *Terminal) WindowsRegistryKeyValue(input string) (*WindowsRegistryValue, error) {
	defer log.Trace(time.Now(), input)

	// Format:
	// "HKLM\Software\Microsoft\Windows NT\CurrentVersion\EditionID"
	//   1  |                  2                         |   3
	//
	// Split into:
	//
	// 1. Root key - extract the root HKEY string and turn this into a handle to get started
	// 2. Path - open this path
	// 3. Key - get this key value
	//
	// If 3 is "" (i.e. the path ends with "\"), then get (Default) key.
	//
	rootKey, regPath, found := strings.Cut(input, `\`)
	if !found {
		err := fmt.Errorf("Error, malformed registry path: '%s'", input)
		log.Error(err)
		return nil, err
	}

	var regKey string
	if !strings.HasSuffix(regPath, `\`) {
		regKey = path.Base(regPath)
		if len(regKey) != 0 {
			regPath = strings.TrimSuffix(regPath, `\`+regKey)
		}
	}

	var key registry.Key
	switch rootKey {
	case "HKCR", "HKEY_CLASSES_ROOT":
		key = windows.HKEY_CLASSES_ROOT
	case "HKCC", "HKEY_CURRENT_CONFIG":
		key = windows.HKEY_CURRENT_CONFIG

View on GitHub (pinned to 0976794618)

Solutions

Include the full path with backslashes, e.g. "HKLM\Software\Microsoft\Windows NT\CurrentVersion\EditionID".
Check the config value that feeds the registry property - ensure any template variables expand to a full path.
Verify you use backslash (\) as the separator, not forward slash.
If you want the Default value of a key, end the path with a trailing backslash (e.g. "HKLM\Software\X\").

Example fix

// before (template/config)
registry = "HKLM"

// after
registry = "HKLM\Software\Microsoft\Windows NT\CurrentVersion\EditionID"

Defensive patterns

Strategy: validation

Validate before calling

func validRegistryPath(p string) bool {
    return strings.Contains(p, "\\") && strings.Index(p, "\\") > 0
}
// call only if validRegistryPath(path)

Type guard

func looksLikeRegistryPath(s string) bool {
    i := strings.Index(s, "\\")
    return i > 0
}

Try / catch

val, err := term.WindowsRegistryKeyValue(input)
if err != nil && strings.Contains(err.Error(), "malformed registry path") {
    // fall back to a default value or hide the segment
    return defaultRegistryValue
}

Prevention

Always use backslash separators in registry paths
Include root key + at least one path component, e.g. HKCU\Software\Key
Verify template variables expand to full paths before render
End the path with \ only when you want the (Default) value

When it happens

Trigger: Calling WindowsRegistryKeyValue (e.g. via a registry template property in a config) with a string lacking a backslash - like "HKLM" alone, an environment variable that resolved to a bare key name, or using forward slashes instead of backslashes.

Common situations: Config typos in a custom prompt's registry lookup; a template variable that expands to an empty or partial path; copying a registry path that uses "/" separators.

Understand the failure class

Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

AI-assisted analysis of JanDeDobbeleer/oh-my-posh@0976794618 (2026-08-31). Data as JSON: /api/errors/84d01ae6bc601c6d. Report an issue: GitHub.