We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

System Error #0000 is displayed. Please explain why this shows up when firefox is very slow to load.

more options

Upon starting or restarting Firefox, it is very, very slow. Screen shows loading, loading, etc until the message "system error #000" is displayed, then I can access my email. Please advise. i am running Fire fox 19.0.2. Please advise

Upon starting or restarting Firefox, it is very, very slow. Screen shows loading, loading, etc until the message "system error #000" is displayed, then I can access my email. Please advise. i am running Fire fox 19.0.2. Please advise

All Replies (1)

more options

Where does that message appear: where your home page normally appears? in a pop-up dialog?


When you have a problem with one particular site -- in this case your home page -- a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Bypass Firefox's Cache

Use Cmd+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

Firefox menu > Preferences > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site:

Tools menu > Page Info > Security > "View Cookies"

Here you can remove your Comcast cookies individually.

Then try reloading the page. Does that help?


If you continue to have the same issue, could you try starting Firefox in Safe Mode -- a standard diagnostic to bypass interference by extensions (and some custom settings). More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is already open, the most direct route is:

  • Help > Restart with Add-ons Disabled
  • In the dialog, click "Start in Safe Mode" (do NOT click Reset)

If Firefox is fully closed, see the article above for the best way to start in Safe Mode for your operating system.

Any difference?