MarkText Won't Open on Mac: Why, and How to Fix It

MarkText won't open on a Mac because its macOS builds are not signed with an Apple Developer ID and not notarized by Apple. macOS blocks the first launch with "MarkText is damaged and can't be opened" or "Apple could not verify 'MarkText' is free of malware". The fix takes a minute: check the download, move MarkText to Applications, then click Open Anyway in System Settings, or run xattr -d com.apple.quarantine /Applications/MarkText.app once in Terminal.

That command comes from MarkText's own release notes. Since September 1, 2026 you also can't install it with Homebrew, which disabled the mark-text cask because it fails Apple's Gatekeeper check. The app itself is maintained: version 0.23.0 shipped on October 21, 2026, and a 0.24.0 release candidate followed on November 3.

I checked every fact on this page on November 5, 2026, on a Mac running macOS 26.3, against MarkText's releases, its documentation and the Homebrew API. If you're weighing MarkText against other apps rather than fixing it, the MarkText comparison covers that.

Why macOS blocks MarkText#

MarkText's installation guide says its packaging sets mac.notarize: false, "so macOS may block the first launch". The 0.23.0 release notes are blunter: "Builds are unsigned (no Apple Developer ID)."

I downloaded the Apple Silicon build of 0.23.0 and asked Gatekeeper about it the way macOS does for a file from the internet. codesign reports an ad-hoc signature with no Team ID, and spctl --assess answers rejected. That is the check Homebrew runs, and the reason it lists for disabling the cask: fails_gatekeeper_check.

Which message you get depends on how the file reached your Mac. Users on MarkText's issue tracker report "is damaged and can't be opened" after a Homebrew install (#4096) and after a direct download (#3889). Apple's own page on the "could not verify" and "damaged" alerts is Safely open apps on your Mac. In both cases macOS refuses the app because it has no signature to trust; the download is usually intact, and step 1's checksum confirms it.

Fix it in four steps#

1. Download the right build and check it#

Get MarkText from the GitHub releases page. There is no universal build: pick marktext-mac-arm64-… on Apple Silicon and marktext-mac-x64-… on an Intel Mac. MarkText needs macOS 13 (Ventura) or later.

Download SHA256SUMS.txt from the same release into the same folder, then in Terminal:

cd ~/Downloads
shasum -a 256 -c SHA256SUMS.txt --ignore-missing

You want OK next to the file you downloaded, DMG or zip: both are listed. I ran this on the 0.23.0 arm64 zip and got OK. Skip this step and the next ones still work, but this is the only check left once Gatekeeper is out of the way.

2. Move it to Applications#

Open the DMG (or unzip the zip) and drag MarkText into Applications. The command below uses that path.

3. Try to open it, then click Open Anyway#

Double-click MarkText. macOS shows the warning; close it. Then, as Apple's Mac User Guide describes for macOS 15, 26 and 27:

1. Choose Apple menu ▸ System Settings, then click Privacy & Security in the sidebar.
2. Scroll to Security and click Open Anyway. The button stays available for about an hour after the blocked launch.
3. Enter your login password and click OK.

macOS saves MarkText as an exception, and it opens normally from then on. The Control-click ▸ Open shortcut from older guides no longer works: Apple removed it in macOS Sequoia.

4. If the message says "damaged": clear the quarantine flag#

MarkText's release notes tell every Mac user to run this once, after copying the app to Applications:

xattr -d com.apple.quarantine /Applications/MarkText.app

The recursive form clears the flag on every file inside the bundle too:

xattr -dr com.apple.quarantine /Applications/MarkText.app

I ran both forms on quarantined copies of the app and checked that the flag was gone afterwards.

"option -r not recognized"? Another xattr, usually installed with Python, sits ahead of Apple's in your PATH and doesn't support -r. My own Mac has one in /Library/Frameworks/Python.framework; a MarkText user hit the same thing (#5611). Call Apple's copy by its full path:

/usr/bin/xattr -dr com.apple.quarantine /Applications/MarkText.app

If Terminal answers "Permission denied", the app isn't owned by your account: put sudo in front and enter your password.

Is it safe?#

Apple's guide puts it plainly: overriding the security settings "is the most common way that a Mac gets infected with malware".

• Unsigned means Apple has no developer identity attached to the build and never scanned it. Signing costs a paid Apple developer account, and MarkText's maintainers ship without one; that says nothing either way about the code.
• Open source means anyone can read the code. MarkText is MIT licensed and its source is on GitHub.
• The checksum proves your file is byte for byte the one the project published. It can't tell you whether that file is safe.

My rule: clear the flag only on a build you downloaded from github.com/marktext and checked against SHA256SUMS.txt. Never do it on a copy from a mirror or a "MarkText for Mac" download site.

If you'd rather not touch Terminal#

• To keep writing Markdown with a free editor: MacDown 3000 is free, MIT licensed, a universal app for macOS 11 or later, and notarized. Gatekeeper accepted its 3000.0.8 build when I checked it. Install it from its site or with brew install --cask macdown-3000. It shows source and preview side by side, so it's a different style from MarkText's inline editing.
• For MarkText's inline style, paid: Typora hides the Markdown syntax as you type, like MarkText. It costs $14.99 once after a 15-day trial. The Markdown editor comparison has prices and macOS requirements for eight editors.
• If you mostly read Markdown: READMEs, docs, or the plans an AI agent writes. That's the case I built MacMD Viewer for, so count me as biased here. It's a read-only viewer, signed with a Developer ID and notarized by Apple, so it opens without any of the steps above. It previews .md files in Finder with Quick Look, renders Mermaid diagrams, and reloads when your editor saves. It costs $19.99 once, before tax, and needs macOS 14 or later. For the detailed comparison, read MacMD Viewer vs MarkText.

The same error hits the original MacDown for the same reason: see MacDown won't open on Mac. For the alert in general, across Markdown apps, read Apple could not verify… is free of malware.

Frequently Asked Questions#

Why does my Mac say MarkText is damaged?#

MarkText's macOS builds are not signed with an Apple Developer ID and not notarized. When a downloaded app carries the quarantine flag and has no valid signature, macOS can report it as damaged even though the file is intact. Clearing the quarantine flag with xattr lets it open.

Why can't I install MarkText with Homebrew anymore?#

Homebrew disabled the mark-text cask on September 1, 2026, with the reason fails_gatekeeper_check. The cask still lists version 0.23.0, but brew no longer installs it. Download MarkText from its GitHub releases page instead.

Is it safe to remove the quarantine flag from MarkText?#

It tells macOS to skip its Gatekeeper check for that one app. MarkText is open source and publishes SHA-256 checksums, so check the download against SHA256SUMS.txt first. The checksum proves the file is the one the project published; it does not prove the code is safe.

What does "option -r not recognized" mean when I run xattr?#

Another xattr, usually installed with Python, comes before Apple's in your PATH and does not support -r. Run Apple's copy by its full path: /usr/bin/xattr -dr com.apple.quarantine /Applications/MarkText.app.

Is there a Markdown editor like MarkText that opens without a warning?#

MacDown 3000 is free, MIT licensed and notarized: Gatekeeper accepted its 3000.0.8 build when I checked it on macOS 26.3. Typora is a paid editor with the same hide-the-syntax style as MarkText.

Sources#

All read or run on November 5, 2026: MarkText 0.23.0 release notes and all releases · MarkText installation guide · Homebrew API for the mark-text cask · MarkText issues #3889, #4096, #5611 · Apple: Safely open apps on your Mac, Open a Mac app from an unknown developer, Updates to runtime protection in macOS Sequoia · MacDown 3000 · Typora. Signature checks: codesign -dv and spctl -a -vvv -t exec on macOS 26.3.