#1 most commonruntime/UILovableBolt.newCursorReplitv0Windsurf
Blank white (or black) screen, nothing loads
The preview or published site shows a completely blank white/black page. Console often shows: Uncaught TypeError / Uncaught ReferenceError ...
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Paste your error →What it means
Your app crashed while it was starting up, so the browser has nothing to draw. It's almost always one specific error hiding in the browser console, and that error names the exact file that broke.
How to fix it: paste this prompt into your AI builder
Fix prompt for Lovable, Bolt, Cursor, Replit, v0, Windsurf
My app shows a blank screen instead of rendering. Do NOT rewrite the app. First, find the root cause: check src/main (or app entry), App, the router, and any component that renders on the first page for (1) imports pointing to files or exports that don't exist, (2) code reading a property of something that can be undefined/null on first render (API data, user, env vars), (3) environment variables used at startup that are missing. Add a top-level React ErrorBoundary that shows the error message on screen instead of a blank page. Tell me the root cause you found before changing anything else, then make the smallest fix. Do not change styling, layout or unrelated features.
If the AI can't fix it: manual steps
- Open the preview/published site in a new tab, press F12 (Cmd+Option+J on Mac), click Console, then reload. Copy the FIRST red error and paste it here or into your AI builder.
- If it only breaks on the published site, compare environment variables between the builder and your host (Vercel/Netlify).
- If the AI can't fix it in 2 tries, restore the last working version from history and re-apply your last change in smaller steps.
Where this happens
Seen in these AI app builders and editors:
LovableBolt.newCursorReplitv0Windsurf
Sources
- https://docs.lovable.dev/prompting/prompting-debugging
- https://www.rapidevelopers.com/lovable-issues/how-to-fix-blank-output-after-building-a-lovable-project
- https://www.reddit.com/r/lovable/comments/1v557u5/lovable_said_the_publish_worked_the_site_was_just/
- https://support.bolt.new/troubleshooting/preview-issues
Related runtime/UI errors
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