We're sorry to hear that Firefox is crashing. In order to assist you better, please follow the steps below to provide us crash IDs to help us learn more about your crash.

The crash report is several pages of data. We need the report numbers to see the whole report.

1. Enter about:crashes in the Firefox address bar and press Enter. A list of Submitted (and Unsubmitted, if any) Crash Reports will appear, similar to the one shown below.
2. Copy the 5 most recent Submitted Report IDs that start with bp- and then go back to your forum question and paste those IDs into the "Post a Reply" box.

Note: If a recent Report ID does not start with bp- click on it to submit the report.

(Please don't take a screenshot of your crashes, just copy and paste the IDs. The below image is just an example of what your Firefox screen should look like.)

Thank you for your help!

More information and further troubleshooting steps can be found in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

Is Firefox launching a downloaded file, or passing parameters using an application-specific protocol (like zoommtg: or msteams:), or connecting to VSCode on a local port, or something else?

We're sorry to hear that Firefox is crashing. In order to assist you better, please follow the steps below to provide us crash IDs to help us learn more about your crash. The crash report is several pages of data. We need the report numbers to see the whole report.

1. Enter about:crashes in the Firefox address bar and press Enter. A list of Submitted (and Unsubmitted, if any) Crash Reports will appear, similar to the one shown below.
2. Copy the 5 most recent Submitted Report IDs that start with bp- and then go back to your forum question and paste those IDs into the "Post a Reply" box.

Note: If a recent Report ID does not start with bp- click on it to submit the report. (Please don't take a screenshot of your crashes, just copy and paste the IDs. The below image is just an example of what your Firefox screen should look like.)

Thank you for your help! More information and further troubleshooting steps can be found in the Troubleshoot Firefox crashes (closing or quitting unexpectedly) article.

I cannot reproduce this issue today. By the way, I checked the content in about:crashes and found no crash data from the past few days. The previous situation was that Firefox froze and became unresponsive (including being unable to close it), so I ended the process directly in Task Manager.

Is Firefox launching a downloaded file, or passing parameters using an application-specific protocol (like zoommtg: or msteams:), or connecting to VSCode on a local port, or something else?

It is not about downloading a file. Instead, it involves a desktop application that requires login. This desktop application redirects to the web for login. After a successful login, Firefox pops up a window prompting to open the application. Once I click "Open Link", Firefox freezes completely and becomes unresponsive to any operations. The only solution is to end the process in Task Manager.

This desktop application redirects to the web for login. After a successful login, Firefox pops up a window prompting to open the application. Once I click "Open Link", Firefox freezes completely and becomes unresponsive to any operations. The only solution is to end the process in Task Manager.

Okay, having looked into this further. I click the gear button in VS Code > Backup and Sync Settings... > then click Signin.

After a few moments, it asks whether to sign in with Github or Microsoft. Choosing Github launches a page in Firefox on https://github.com/login/oauth/select_account. Cool. Click Authorize, wait several seconds for the redirect, then another, then:

Firefox can’t establish a connection to the server at 127.0.0.1:portnum

When I open the Network Monitor on the page (Ctrl+Shfit+E) and Ctrl+Shift+R to reload the page, I see NS_ERROR_CONNECTION_REFUSED. So I can't replicate your scenario where, presumably, the system accepts with the request. Maybe it's a Windows configuration question; I can't look into it right now.

But meanwhile, this does fit the scenario of Firefox submitting a request back to VS Code using its listening port on 127.0.0.1 (localhost). I don't know why that would hang Firefox indefinitely rather than, say, just timing out.