Hi, I'm not sure what is causing that. Could you test in Firefox's Safe/Troubleshoot Mode? In that mode, Firefox temporarily deactivates extensions, hardware acceleration, any userChrome.css/userContent.css files, and some other advanced features to help you assess whether these are causing the problem.

If Firefox is running:

You can restart Firefox in Safe/Troubleshoot Mode using either:

• "3-bar" menu button > Help > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)
• (menu bar) Help menu > Troubleshoot Mode... (before Fx88: Restart with Add-ons Disabled)

and OK the restart. A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

If Firefox is not running:

Hold down the Shift key when starting Firefox. (On Mac, hold down the option/alt key instead of the Shift key.) A small dialog should appear. Click the Open button (before Fx88: "Start in Safe Mode" button).

Note: Don't use the Refresh without first reviewing this article to understand what will be deleted: Refresh Firefox - reset add-ons and settings.

Any improvement?

I actually did this before submitting my error for assistance, but just did it again and am still getting the XML PARSING ERROR.

Hmm, where is that coming from?

Could you update your connection setting here:

• Windows: "3-bar" menu button (or Tools menu) > Settings (previously "Options")
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the tiny search box at the top of the page, type proxy and Firefox should filter to the "Settings" button, which you can click.

Select "No proxy" and click OK.

Any difference?

No difference. Getting the same error

Maybe some Firefox program files are damaged. What I usually recommend in that situation is:

Clean Re-install

This takes about 5 minutes. It's not about your settings, it's about making sure the program files are clean (no inconsistent or alien code files). As described below, this process does not disturb your existing settings. It's not essential to uninstall Firefox, but you can if you like, saying No to any request about removing personal data.

If you want to make a backup first just in case, see: Back up and restore information in Firefox profiles

(A) Download a fresh installer for Firefox to a convenient location:

https://www.mozilla.org/firefox/all/

(B) Exit out of Firefox (if applicable).

If you have Microsoft Office installed locally, please change your system default browser to Internet Explorer temporarily before the next step.

(C) Using File Explorer (hold down the Windows key and press E to launch it), right-click > rename the program folder as follows (you might have one or both):

C:\Program Files (x86)\Mozilla Firefox =to=> C:\Program Files (x86)\OldFirefox

C:\Program Files\Mozilla Firefox =to=> C:\Program Files\OldFirefox

(D) Run the installer you downloaded in step (A). It should automatically connect to your existing settings.

Any improvement at your next startup?

1. I don't have Microsoft Office and don't use Internet Explorer.

2, When I try to find my profile I get the XML PARSING error. I'm afraid to go any further. I'm not technically sophisticated and am concerned that the problem is getting worse. I just want my computer back to where it was before the update.

I installed the version seems to be working. Thanks for you assistance.