How to Show Markdown Text in Preview in Kanboard on Windows 10

To display rendered Markdown text in Kanboard’s preview on Windows 10, you must ensure the application is using a modern browser engine that supports the required JavaScript libraries. The most common cause for raw Markdown syntax appearing instead of formatted text is an outdated or incompatible web view component within the Kanboard desktop wrapper, or simply viewing the page via a local file path rather than through the proper HTTP server.

Understanding the Preview Mechanism

Kanboard relies heavily on client-side JavaScript to parse Markdown syntax into HTML before rendering it in the preview pane. This process typically uses libraries like marked.js or similar parsers embedded within the application's frontend assets. When you click the "Preview" tab while editing a task description, comment, or project documentation, the browser (or the embedded web view) executes this script to transform your input into bold headers, lists, and links. If you see the raw asterisks, hashes, and brackets, it indicates that the JavaScript execution failed or was never triggered correctly. This is not usually a configuration setting within Kanboard itself, but rather an environmental issue with how the interface is being served or viewed on your Windows 10 machine. Understanding this distinction helps you target the right fix, whether it involves restarting services, clearing caches, or adjusting how you access the application.

Verify You Are Using the HTTP Server

The most frequent mistake users make on Windows is attempting to open the Kanboard interface by double-clicking the index.php file directly from File Explorer. This loads the page via the file:// protocol. Modern browsers enforce strict security policies known as CORS (Cross-Origin Resource Sharing) and may block local JavaScript modules or AJAX requests when accessed this way. Consequently, the preview function fails silently, leaving the raw text visible. To resolve this, you must run Kanboard through its built-in PHP development server or a proper web server like Apache or Nginx. If you are using the standard distribution, open your command prompt, navigate to the Kanboard root directory, and execute the following command:

php -S localhost:8080

Once the server starts, access the application by typing http://localhost:8080 into your web browser. Ensure you use http:// and not file://. This ensures that all relative paths for JavaScript assets are resolved correctly, allowing the preview engine to load and execute properly. If you are already using a server, skip to the next section regarding cache issues.

Clear Browser Cache and Local Storage

Even when running on the correct HTTP server, stale data can prevent the preview from updating. Browsers aggressively cache static assets like JavaScript files to improve performance. If you recently updated Kanboard or changed themes, your browser might still be holding onto an old version of the preview script that contains bugs or incompatibilities with your current setup. You should perform a hard refresh to force the browser to re-download these assets. In most Windows browsers, you can do this by pressing Ctrl + F5 while the preview tab is active. Alternatively, you can clear the cache manually by navigating to your browser settings, finding the "Privacy and Security" section, and selecting "Clear browsing data." Ensure you check both "Cached images and files" and "Cookies and other site data." After clearing, log back into Kanboard and test the preview again. For more details on managing system resources and permissions on Windows, you might find our guide on Cannot change permissions in Windows 10 because the file is being used by another process helpful, as file locking can sometimes interfere with server updates.

Check for Conflicting Extensions

Browser extensions designed for ad-blocking, privacy, or code formatting can sometimes interfere with the JavaScript execution required for Markdown parsing. Extensions like uBlock Origin or various script blockers may identify the Kanboard preview scripts as unnecessary telemetry or ads and block them. This results in the preview pane remaining empty or showing raw text. Temporarily disable all browser extensions and reload the Kanboard page. If the preview works correctly after disabling them, re-enable them one by one to identify the culprit. You may need to add an exception for your Kanboard domain in the extension's settings. Additionally, ensure that you are not using any developer tools that might be intercepting network requests in a way that breaks the preview functionality.

Verify Server Configuration and PHP Version

While less common, server-side configurations can also impact the frontend experience. Kanboard requires PHP 7.4 or higher. If your PHP installation is outdated, some internal functions may fail, leading to unexpected behavior in the UI. Check your PHP version by creating a simple info.php file with and accessing it via your browser. Furthermore, ensure that the mod_rewrite module is enabled if you are using Apache, as this affects URL routing which the frontend JavaScript relies on for API calls. For Nginx users, verify that your rewrite rules match the standard Kanboard configuration. Incorrect routing can cause the preview API endpoint to return errors, which the frontend catches and displays as raw text or error messages.

Frequently Asked Questions

Why does the preview work for some tasks but not others?

This usually happens when specific Markdown syntax triggers a JavaScript error in older parser versions. Complex nested lists or unusual character encodings can cause the parser to crash. Try simplifying the text to basic paragraphs and headings to isolate the problematic element.

Can I use Kanboard without a web server on Windows?

No, Kanboard is a web application and cannot function correctly by opening local files directly. You must use the built-in PHP server or install Apache/Nginx to serve the application over HTTP. This ensures all asset paths and API endpoints resolve correctly.

Does clearing cookies affect my Kanboard login?

Yes, clearing cookies will log you out of Kanboard. However, this is often necessary to resolve session-related caching issues. Simply log back in after clearing the data; your tasks and projects remain stored on the server, not in your browser cookies.

Is there a keyboard shortcut to toggle the preview?

Kanboard does not have a default global keyboard shortcut for toggling the preview pane, but you can switch tabs using the arrow keys or mouse. Some custom plugins may add shortcuts, so check your plugin settings if you need faster access.

What should I do if the preview shows a blank white box?

A blank preview box typically indicates a JavaScript error preventing the DOM from being populated. Open your browser's Developer Tools (F12), go to the Console tab, and look for red error messages. These messages will tell you exactly which script failed to load or execute.