How to preview Markdown with Quick Look on a Mac

To preview a Markdown file on a Mac, select it in Finder and press Space. Quick Look gives you a fast glance without opening an editor. When the document needs full rendering, editing, or review of an external rewrite, open the same file in Downright.

Use Finder and Space for the glance

1. Open a Finder window and select the .md file.
2. Press Space to open Quick Look.
3. Press Space again to close the preview.

Quick Look is ideal for checking a README, plan, or short note. It is not a full editing surface, and a narrow Finder preview can make long documents harder to read.

If Quick Look shows raw text

1. Confirm the file has a Markdown extension such as .md, .markdown, .mdx, .qmd, or .rmd.
2. Close the preview and open it again after installing the signed Downright app in /Applications; extensions cannot register reliably from a temporary disk image or App Translocation.
3. Use down doctor to check the installed bundle, Quick Look extensions, file association, and CLI path. The command reports diagnostics locally and supports --json for support logs.

Some Macs need Finder or Quick Look to reload its extension cache after an app installation. Reopening Finder is a lower-impact first step; reset system caches only when the diagnostic output points to registration rather than a missing bundle.

Use Downright for the document

Downright provides a native reading and editing surface for the same local file. Headings, tables, callouts, tasks, footnotes, math, Mermaid, and code stay together. The source remains the authority.

When another process changes the open file, Downright marks the external rewrite and lets you keep your local version or take the other version instead of silently replacing dirty work.

Quick decision

• Two-second check: Finder and Quick Look.
• Read or edit a long file: Downright.
• Review an agent rewrite: Downright with the file open.

This guide is published by Downright. Product behavior is described from the native app’s current bundle and source; Quick Look-only preview remains the lighter choice when you do not need editing or review.