How to Set the Default Markdown Editor on Mac

You double-click a .md file and Xcode opens. Or TextEdit. Or whatever installed itself most recently and claimed the file type.

macOS decides this per file extension, and it can be changed permanently in about ten seconds.

The manual way

This works for any file type, not just Markdown.

1. Right-click any .md file in Finder
2. Choose Get Info, or press ⌘ I
3. Find the Open with section and expand it
4. Pick the app you want from the dropdown
5. Press Change All, then confirm

That is it. Every .md file on your Mac now opens in that app.

The step people miss is Change All. Choosing an app in the dropdown without pressing it only changes that one file, which is why the problem seems to come back.

The one-click way

Some Markdown apps offer a setting that registers them as the handler directly. TypeFire has one in Settings, which registers it against the standard Markdown file type in a single click, no Finder trip required.

Why it keeps reverting

Three common causes.

You changed the file, not the type. Without pressing Change All, you set an override for that single file.

An app re-claimed it on update. Some apps, developer tools especially, re-register themselves as handlers when they update. Xcode is the usual culprit. Redo the Get Info steps.

Different extensions. Setting .md does not set .markdown or .mdown. They are separate types as far as Launch Services is concerned, so repeat the process for each, or rename the files.

The nuclear option

If Launch Services has genuinely got confused and nothing sticks, rebuilding its database usually clears it:

/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user

Then restart Finder. This resets all file associations, so treat it as a last resort rather than a first move.

What to actually set it to

Depends on the job:

• Reading mostly? Set an app that renders on open, and separately install a Quick Look extension so you rarely need to open anything at all
• Writing long form? Typora or iA Writer
• Notes and linking? Obsidian
• Files scattered across projects? Something that opens fast and renders immediately, since you are glancing rather than composing

Worth pairing with Quick Look

Setting a default editor solves double-clicking. It does not solve the more common case, which is wanting to read a file without opening anything.

Those two together, a default app for editing and Quick Look for reading, is the setup that actually removes the friction. TypeFire does both: one-click default registration, plus a Quick Look extension so space in Finder renders any .md file.

Download for Mac or read the Markdown tour.