When it won't open

"MarkPad is damaged and can't be opened"

The message“MarkPad” is damaged and can’t be opened. You should move it to the Bin.

Nothing is damaged. macOS says this when a downloaded app carries the quarantine flag and isn't signed by a paid developer account. Right-clicking and choosing Open won't get past this one, so clear the flag instead.

1. Drag MarkPad into Applications.
2. Open Terminal and run:

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

3. Open MarkPad normally.

You only do this once. The flag is gone for good, so MarkPad opens with a double-click from now on, including after you restart.

The command removes the download flag from one app you chose to install. Run it on things you trust and nothing else.

"Apple cannot check it for malicious software"

The message“MarkPad” can’t be opened because Apple cannot check it for malicious software.

1. Double-click MarkPad and dismiss the warning.
2. Go to System Settings, Privacy & Security, scroll to Security and click Open Anyway. The button only shows for about an hour after the blocked launch.
3. Confirm with your password or Touch ID.

On macOS 14 and earlier you can skip that: right-click the app, choose Open, then Open in the dialog. macOS 15 removed that shortcut for unsigned apps.

macOS remembers either way, so it's a first launch step only.

It quits straight away, or the dmg won't install

Wrong build for the chip.

1. Apple menu, About This Mac. A chip line reading Apple M something means Apple silicon.
2. Download aarch64 for Apple silicon, x64 for Intel.
3. Drag it into Applications and replace the copy that's there.

"Windows protected your PC"

The messageWindows protected your PC. Microsoft Defender SmartScreen prevented an unrecognised app from starting.

Unrecognised publisher, not detected malware.

1. Click More info.
2. Click Run anyway.

If the download itself was blocked, open your browser's downloads list and choose Keep.

The installer disappears from Downloads

Some scanners quarantine unsigned installers without saying so.

1. Open your antivirus, find the quarantine list, restore the file.
2. Or add it to exclusions and download again from the releases page.
3. Right-click the exe, Properties, tick Unblock if it's there, then OK.

The window is blank, or an error names WebView2

MarkPad uses the WebView already on your machine. Windows 11 and current Windows 10 have it. Stripped LTSC and Server images don't.

1. Install the Evergreen Runtime from Microsoft.
2. Start MarkPad again.

"This app can't run on your PC"

The build is 64-bit x86 only.

1. Check Settings, System, About, and read System type.
2. 32-bit or Arm, such as a Surface Pro X, has no build today. Say so on an issue if you want one.

Double-clicking a .md file opens the old editor

Installing MarkPad doesn't take the association off anything. Hand it over when you want to.

• Windows: right-click a .md file, Open with, Choose another app, pick MarkPad, tick always use this app.
• macOS: right-click a .md file, Get Info, pick MarkPad under Open with, then Change All.

The Linux package won't install

Take the .deb on Debian, Ubuntu and anything built on them, and the .rpm on Fedora. Either one pulls in WebKitGTK 4.1 if it's missing.

The .deb needs Debian 12 or Ubuntu 22.04 at least. Older releases ship a glibc and WebKitGTK too old to run it, and there's no build for them.

You lost what you'd typed

There's no autosave and no crash recovery. The dialog about unsaved changes is the only warning, and every route out of the app shows it.

Save as you go with Ctrl+S or ⌘+S.