Unity WebGL Build Shows Black Screen - How to Fix (Browser Compatibility)

Problem: Your Unity WebGL build loads in the browser (progress bar may complete) but the game view stays black. The tab does not crash; you just see a black canvas where the game should be.

Quick Solution: Check the first scene in Build Settings, ensure a camera is active and rendering, verify the WebGL canvas and template, and test in multiple browsers. Most black-screen cases are caused by the wrong scene loading, camera clear flags, or browser-specific rendering.

This guide walks you through the most common causes and fixes so your WebGL build displays correctly across browsers.

Why WebGL Builds Show a Black Screen

A black screen (without a crash) usually means:

• No camera or camera not rendering – the first scene has no active camera, or the camera’s culling mask or clear flags hide everything.
• Wrong scene in Build Settings – the WebGL player loads a scene that is empty, a loading stub, or not the one you expect.
• Canvas or resolution mismatch – the WebGL canvas size is zero, or the game renders at a different resolution than the canvas.
• Graphics API or shader issues – the browser’s WebGL implementation rejects shaders or the context, so nothing is drawn.
• First-frame timing – the first scene or camera is not ready when the first frame is drawn (e.g. async load not finished).

Fixing these in order (Build Settings → camera → canvas → browser) usually resolves the black screen.

Solution 1: Build Settings – Correct First Scene and Scenes in Build

If the first scene in the build is wrong or empty, the player will show a black screen.

Step-by-Step Fix

1. Open Build Settings

   • Go to File > Build Settings.
   • Ensure WebGL is the selected platform (switch platform if needed).

2. Set the First Scene

   • In Scenes In Build, the top scene (index 0) is the one that loads first.
   • Drag your main game scene (the one with a camera and content) to index 0.
   • Remove or reorder any “loading” or empty scenes so they do not load first unless you intentionally have a loader that transitions to the game.

3. Include All Required Scenes

   • Add every scene the game needs (e.g. main menu, level 1). Do not rely on “add open scenes” alone; confirm the list matches your flow.

4. Rebuild and Test

   • Build for WebGL again and run in a browser. If the correct scene loads and has a camera, the black screen may be fixed.

Verification: After the loader (if any), the first visible content is your game scene, not a blank or empty scene.

Solution 2: Camera and Rendering

If the first scene has no active camera or the camera does not draw, the canvas will be black.

Step-by-Step Fix

1. Check for an Active Camera

   • Open the scene that loads first (index 0 in Build Settings).
   • Ensure there is at least one Camera (or URP/HDRP camera) in the hierarchy.
   • The camera must be active (GameObject enabled and Camera component enabled).

2. Camera Clear Flags and Culling

   • Select the camera. In the Inspector, set Clear Flags to Solid Color or Skybox so the background is drawn (not “Don’t Clear”, which can leave garbage or black).
   • Set Culling Mask to include the layers your objects use (e.g. Default). If the mask excludes everything, the camera will render only the clear color (or black).

3. Background Color

   • If using Solid Color, set Background to a visible color (e.g. blue or gray) to confirm the camera is rendering. If you see that color instead of black, the issue was camera or content; then switch back to Skybox or your intended background.

4. Multi-Camera Setup

   • If you use multiple cameras, ensure the one that should draw the main view has the correct Depth (higher depth draws on top) and is enabled. Disabled or zero-depth cameras can leave the screen black if they are the only ones in the scene.

5. Rebuild and Test

   • Build again and test. If the camera is correct, you should see the clear color or your scene.

Verification: You see at least the camera background (solid color or skybox); the canvas is no longer black.

Solution 3: WebGL Template and Canvas

Some WebGL templates or canvas setups can cause a black screen if the canvas is missing, sized to zero, or not attached correctly.

Step-by-Step Fix

1. Check Player Settings – WebGL Template

   • Go to Edit > Project Settings > Player, then the WebGL tab.
   • Under Resolution and Presentation, check Default Canvas Width and Default Canvas Height. They should be non-zero (e.g. 960×600 or match your design).
   • If you use a Custom Template, open the template’s index.html and ensure the canvas element exists and is not given 0×0 size by CSS or script.

2. Canvas Resizing

   • In the template or in your own script, avoid forcing the canvas to 0×0. Some fullscreen or responsive scripts resize the canvas; if they run before Unity is ready or have a bug, the canvas can end up zero-sized and appear black.

3. Try the Default Template

   • Temporarily switch to the Default WebGL template (no custom template) and rebuild. If the black screen goes away, the issue is in the custom template (canvas, CSS, or script).

4. Rebuild and Test

   • Build with the default or fixed template and test in Chrome and one other browser.

Verification: The WebGL canvas has a non-zero size and the game view is visible (or at least the camera clear color).

Solution 4: Browser-Specific and Graphics Issues

Some browsers or devices reject certain WebGL features or shaders, which can result in a black screen without a clear error.

Step-by-Step Fix

1. Open Browser Developer Tools

   • Press F12 (or equivalent) and open the Console tab.
   • Look for WebGL errors (e.g. “context lost”, “shader compilation failed”, or “unsupported”). These can explain a black screen.

2. Test in Multiple Browsers

   • Test in Chrome, Firefox, and Safari (and Edge if you support it). If the screen is black only in one browser, the issue is likely compatibility or a bug in that browser’s WebGL stack.

3. Reduce Graphics for Problem Browsers

   • In Edit > Project Settings > Quality, you can use a lower quality level for WebGL. Try the lowest setting and see if the black screen disappears (e.g. simpler shaders or no shadows).
   • In Player Settings > WebGL, under Other Settings, you can try Auto Graphics API or a single WebGL 2.0 (or 1.0 fallback) to see if one works where the other does not.

4. Check for Shader Errors

   • If the console reports shader compilation failures, fix or replace the failing shaders (e.g. use a WebGL-compatible variant or a simpler fallback). Broken shaders can leave the screen black.

5. Rebuild and Test

   • After changes, rebuild and test again in the browser that showed the black screen.

Verification: The game renders in all browsers you support, or you see a clear error in the console that you can address (e.g. shader or context).

Prevention Tips

• Always set the correct first scene in Build Settings before building WebGL, and confirm that scene has an active camera.
• Test WebGL early and often in at least two browsers so you catch canvas, camera, or compatibility issues before release.
• Use Solid Color clear (or Skybox) on the main camera and avoid “Don’t Clear” unless you have a specific post-processing or multi-camera reason.
• Document supported browsers (e.g. Chrome, Firefox, Safari, Edge) so users know what to expect.

When the Screen Is Still Black

• Black after progress bar: Usually the first scene or camera. Recheck Build Settings scene order and camera in that scene.
• Black in one browser only: Check that browser’s console for WebGL or shader errors; try a lower quality or different graphics API.
• Black with no errors: Confirm canvas size is non-zero and the default WebGL template works; then reintroduce custom template or scripts one by one.
• Black then crash: May be memory or threading; see Unity WebGL Build Crashes in Browser for crash-focused fixes.

Related Help and Guides

• Unity WebGL Build Crashes in Browser - How to Fix for crashes and freezes.
• Unity Build Fails with Out of Memory Error for build and memory issues.
• Web Game Deployment Issues - Complete Solution Guide for hosting and deployment.

For more on Unity deployment, see the building and publishing section of our Unity guide.

Bookmark this fix for quick reference when your WebGL build shows a black screen. If this article helped, share it with other developers shipping to the web.