lighthouse: ☔️ Protocol error (Tracing.start): Tracing is already started

NOTICE FOR DUPLICATE BUG FILERS: The only known fix for this is usually completely restarting the browser, and sometimes with a completely fresh profile.

Lighthouse Version: 1.2.2 Chrome Version: 57.0.2937.0 Error Message: Protocol error (Tracing.start): Tracing is already started Stack Trace:

   at ExtensionConnection.handleRawError (chrome-extension://blipmdconlkpinefehnmjammfjpmpbjk/scripts/lighthouse-background.js:7377:11)
   at Object.chrome.debugger.sendCommand.result [as callback] (chrome-extension://blipmdconlkpinefehnmjammfjpmpbjk/scripts/lighthouse-background.js:7526:33)
   at safeCallbackApply (extensions::sendRequest:21:15)
   at handleResponse (extensions::sendRequest:74:7)```

About this issue

Original URL
State: closed
Created 8 years ago
Reactions: 4
Comments: 25 (8 by maintainers)

Most upvoted comments

Here’s an attached screen shot from www.yahoo.com site audit. Tested on Version 73.0.3681.0 (Official Build) canary (64-bit). The error message says “Something went wrong with recording the trace over your page load. Please run Lighthouse again.”, in case that helps. I’ve quit/closed the app, and restarted, and it still happens. screen shot 2019-01-23 at 4 49 04 pm

mssodhi on Jan 24, 2019

@jamesshannon it does yes. 😃

chromium location

paulirish on Sep 18, 2018

I am facing the same issue, Using chrome browser and when I use lighthouse on my website’s admin pages got the below error.

Chrome Version 116.0.5845.96

Protocol error (Tracing.start): Tracing has already been started (possibly in another tab).

Channel: DevTools
Initial URL: https://www.*******.com/admin/catalog/product/edit/id/8565/key/441e91a2d205ac73d47cfcab2cf954c142e0a40a7ce450d74b74366b7fe8d23f/
Chrome Version: 116.0.0.0
Stack Trace: w: Protocol error (Tracing.start): Tracing has already been started (possibly in another tab).
    at devtools://devtools/bundled/devtools-frontend/front_end/services/puppeteer/puppeteer.js:1:6938
    at new Promise (<anonymous>)
    at j.send (devtools://devtools/bundled/devtools-frontend/front_end/services/puppeteer/puppeteer.js:1:6871)
    at ProtocolSession.sendCommand (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:604:258)
    at Trace.startSensitiveInstrumentation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:152:471)
    at async devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:610:696
    at async collectPhaseArtifacts (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:610:827)
    at async _navigation (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:623:67)
    at async _navigations (devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:625:637)
    at async devtools://devtools/bundled/devtools-frontend/front_end/third_party/lighthouse/lighthouse-dt-bundle.js:625:260

neha023 on Oct 2, 2023

Seems like it fails if I’m starting two different traces at the same time? I did it from two different tabs.

jontejj on Sep 28, 2017