Lovable: Live preview couldn't start

What it means in plain English

The preview is the live app on the right side of the Lovable editor. Lovable's preview guide says it is a staging environment for your latest work. Visitors see the published snapshot, which changes only when you publish. The preview and the published app share the same backend and data, so a database change shows up in both.

Lovable's preview guide names three failures: "Live preview couldn't start", "Live preview lost connection", and "Live preview stopped responding". Each one has a Try again button. A blank white screen on the published URL is a different page: Lovable blank screen after publish.

Likely causes

• The preview environment was paused. Lovable shows Still building? and says to click Keep building. Pausing does not change the published site.
• The start failed after automatic retries, which is "Live preview couldn't start".
• The connection dropped, which is "Live preview lost connection". Lovable says it tries to recover first.
• The app crashed, which is "Live preview stopped responding".
• The preview is white because of an error in the app itself. Lovable says that is the usual cause of a blank preview.

How to fix it, step by step

1. Click Refresh above the preview. If it is still wrong, hold Shift and click Refresh. Lovable says that restarts the preview environment and resolves most loading issues. A hard refresh is Cmd+Shift+R on Mac or Ctrl+Shift+R on Windows and Linux.
2. If the message is "Starting live preview…" for several minutes, wait. Lovable retries a failed start. If your device is offline, it waits and resumes when the connection returns. You do not refresh for that case. If it stays, check the internet connection.
3. For "Live preview couldn't start" or "Live preview lost connection", check the connection and click Try again. If it returns, Shift+Refresh. On "couldn't start", Dismiss shows an earlier version when one is available.
4. For "Live preview stopped responding", click Try again. If it returns, ask in the project chat: The preview shows "Live preview stopped responding", investigate and fix it.
5. For a white preview, ask: The preview is white, investigate and fix it.
6. If you want the preview to update only when a change finishes, turn Live preview off under Project settings, then General, then Preview. Lovable says that does not change the published app.

How to check it worked

• The preview draws the latest editor version and you can click through it.
• The error line and the Try again button are gone.
• The published URL is unchanged until you publish. A shared preview link still shows the in-progress version.

If the preview works but publishing fails, see Lovable app not deploying. If the Supabase view says Supabase connection issue, see Lovable Supabase connection broke.

Sources

• https://docs.lovable.dev/features/projects/preview (opens in a new tab)