Windows 10 reached EOS (end of support) on October 14, 2025. For more information, see this article.

Avatar for Username

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

This thread was archived. Please ask a new question if you need help.

error when starting firefox

  • 4 replies
  • 59 have this problem
  • 5 views
  • Last reply by rrrash

rrrash
rrrash

[Exception... "Could not convert JavaScript argument arg 0 [nsISupports.QueryInterface]" nsresult: "0x80570009 (NS_ERROR_XPC_BAD_CONVERT_JS)" location: "JS frame :: resource://cck2/Preferences.jsm :: get _prefSvc :: line 544" data: no]

get _prefSvc@resource://cck2/Preferences.jsm:544:19 _get@resource://cck2/Preferences.jsm:87:1 get@resource://cck2/Preferences.jsm:81:12 init@resource://cck2/CCK2.jsm:149:25 @cck2.cfg:59:1

[Exception... "Could not convert JavaScript argument arg 0 [nsISupports.QueryInterface]" nsresult: "0x80570009 (NS_ERROR_XPC_BAD_CONVERT_JS)" location: "JS frame :: resource://cck2/Preferences.jsm :: get _prefSvc :: line 544" data: no] get _prefSvc@resource://cck2/Preferences.jsm:544:19 _get@resource://cck2/Preferences.jsm:87:1 get@resource://cck2/Preferences.jsm:81:12 init@resource://cck2/CCK2.jsm:149:25 @cck2.cfg:59:1

Chosen solution

I uninstalled and reinstalled it. The issue is fixed now. Not sure exactly what was causing it.

-Ravi

Read this answer in context 👍 0

All Replies (4)

philipp
philipp
  • Moderator

hi, are you using firefox in an enterprise environment? if yes please contact your it admin as the central configuration they are using for firefox looks like it's breaking. otherwise you could manually delete the firefox program folder and reinstall firefox which should fix this problem...

rrrash
rrrash Question owner

thanks Phillip

Yes, in an enterprise env. I will reach out to the admins. Not sure what would conflict to cause this error.

thanks,

-Ravi

Shadow110
Shadow110

Hello,

I am glad to hear that your problem has been resolved on this end only. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily. Thank you for contacting Mozilla Support.

rrrash
rrrash Question owner

Chosen Solution

I uninstalled and reinstalled it. The issue is fixed now. Not sure exactly what was causing it.

-Ravi