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Receiving XML Parsing Error: undefined entity on New Install

  • 6 replies
  • 21 have this problem
  • 17 views
  • Last reply by cor-el

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Hello, I'm moving a Profile from a Linux box (51.0.1 (64-bit)) to a new Firefox install on Windows10. When I start Firefox, I receive this error: XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 1879, Column 7:

<menuitem label="&syncedTabs.context.openAllInTabs.label;"
</pre>

I've gone back to the original install on Ubuntu and have disabled all the Add-ons & Extensions and after copying back it still fails with the same error. I've tried installing in both 32bit and 64 bit mode. When in Safe mode I've also unchecked Hardware Acceleration and made sure the Default Theme is being used. What is frustrating is that it worked once and for some reason (insanity?) I decided to try again and now can't get it to load at all.

Your thoughts would be appreciated.

Thank you

Hello, I'm moving a Profile from a Linux box (51.0.1 (64-bit)) to a new Firefox install on Windows10. When I start Firefox, I receive this error: XML Parsing Error: undefined entity Location: chrome://browser/content/browser.xul Line Number 1879, Column 7: <menuitem label="&syncedTabs.context.openAllInTabs.label;" I've gone back to the original install on Ubuntu and have disabled all the Add-ons & Extensions and after copying back it still fails with the same error. I've tried installing in both 32bit and 64 bit mode. When in Safe mode I've also unchecked Hardware Acceleration and made sure the Default Theme is being used. What is frustrating is that it worked once and for some reason (insanity?) I decided to try again and now can't get it to load at all. Your thoughts would be appreciated. Thank you

Modified by Stocksight

Chosen solution

It was the extensions.json file that caused the error message. I skipped this file when I wrote over the original Profile installation files with my backup Profile and it worked. I am able to now open Firefox. Do I need this file for anything? What function does it perform? Thank you

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All Replies (6)

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This issue can be caused by an extension that isn't working properly.

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

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cor-el, thank you for responding. I have all the Extensions & Add-ons disabled, unchecked Hardware Acceleration and it seems to be using the standard Theme. I am able to start in Safe Mode but am not sure what else could be the problem.

I then went in and removed all the Extensions and restarted and still no luck.

Thank you

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The message mention a syncedTabs entity, so that should give a clue.

  • menuitem <="" label="&syncedTabs.context.openAllInTabs.label;"

What Firefox locale (user interface language) are you using in case there is a problem with the translated strings?

Are you using the Firefox version from the repositories of your Linux distribution or the Firefox version from the official Mozilla servers?

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cor-el, it is English. I am streaming the standard Windows build directly from the Mozilla servers. Thank you

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Chosen Solution

It was the extensions.json file that caused the error message. I skipped this file when I wrote over the original Profile installation files with my backup Profile and it worked. I am able to now open Firefox. Do I need this file for anything? What function does it perform? Thank you

Modified by Stocksight

more options

The extensions.json file stores all data about installed extensions (i.e. is the extensions registry). If this file wouldn't match with the extensions in the extensions folder then this could confuse Firefox.