Commonly opened with
  • Varies by the application that created it
Supported platforms
  • Windows
  • macOS
  • Linux
Editable?
Partially / with the right tool
Viewable without special tools?
Usually, yes
Inherent format risk
Generally low risk
Safety guidance (not a guarantee)

A generic or catch-all format. What it can actually do depends entirely on the application that created it — treat it with the same caution as any file from an untrusted source.

Check another filename

File extension lookup

No upload, no sign-up — everything is analyzed locally in your browser.

Frequently asked questions

What is a .lock file?

A marker file used by an application or package manager to indicate a resource is in use, or to pin exact dependency versions (e.g. package-lock.json).

Can I edit a .lock file?

Partially. .lock files can be edited with the right tool (such as Varies by the application that created it), but not with just any text editor.

Does having a .lock extension mean the file is safe?

No single extension can guarantee that. A generic or catch-all format. What it can actually do depends entirely on the application that created it — treat it with the same caution as any file from an untrusted source. Always consider where the file came from, not just its name.

Privacy: The lookup above runs entirely in your browser. Nothing you type is uploaded, logged, or sent anywhere.

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