May 28, 2007

FX2 Extension installation problem:Error 203

wilkinsonbj wrote:
I've just installed Fire Fox 2 and have tried to
install some Add Ons/Extensions and every time get the message:
"Firefox could not install the file because: Unexpected installation error. Review the error Console log for more detail. -203"

The console log shows:
Error: uncaught exception: [Exception... "
Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMWindowInternal.focus]"
nsresult: "0x80004005 (NS_ERROR_FAILURE)" location:
"JS frame :: chrome://browser/content/browser.js :: BrowserOpenAddonsMgr :: line 5738" data: no]

Error: e.location.getItemLocation( has no properties
Source File: file:///C:/PROGRA~1/MOZILL~1/components/
Line: 4050

Can someone give me a clue how to sort this please.


Are you one of the many suffering like this? A number of solutions have been provided here about the 203 nsExtensionManager.js error, all with varying results. But I think the most fail proof solution is slash and burn.

Update; So that no one misses the point. Deleting the extensions.rdf or replacing it may work depending on the corruption level of the config files in your profile. You are advised to try this before attempting the procedure below, which is meant to 'weed' out any and all corrupt config files to prevent the secondary recurrent bugs

THIS PROCESS TAKES 5-10 Minutes at the most.

(Firefox must be closed first before starting)

1. Go to your Tools>Add Ons
list down the names of all your extension on paper, (including the version)

2. Go to
Documents and Settings> User Name>Application Data> Mozilla>Firefox> Profiles,
find a copy of your latest back up bookmark file and save it somewhere easy to find like the desktop.( the one with today's date or the most recent one)

3. Go to Documents and Settings> User Name>Application Data
and delete the Mozilla folder. (leave no trace, delete also from recycle bin)

4. When you restart Firefox it is refreshed.. Select "Import Nothing" on the wizard that pops up.

5. You can then reinstall all the add-ons, WITHOUT any errors now.
(the note will help you remember which ones)

6. After, go onto the Bookmarks Organiser and import your bookmarks from the desktop.

Your Firefox will now work good as new.

I have posted a similar article on MozillaZine Forum. Hope this helps


Anonymous said...

Quicker and simpler:
"Delete (or better, rename/backup) the file extensions.rdf. Firefox will recreate it when it is next started.
This solved the problem for me. No need to create a new profile."

Read more at:
This works for me too.

diddy47 said...

thanx for the comment. I am aware of solutions like the one u proposed. The solution I offered was a 'slash and burn' solution for anyone who was having recurring myself...i tried all that worked for a few days but the bug would reappear saying the same or different error..

diddy47 said...

For example....

Trent Larson wrote on 2006-11-10:

I have tried all these solutions:
- adding the patch (but it complains on the line BEFORE the patch)
- renaming extensions directory
- the extensions.rdf file (because that file doesn't exist anywhere under my firefox directory)
- manually downloading the XPI file and opening it (with File->Open and with Tools->Add-ons)

I still get the problem. Any suggestions?

Anonymous said...


I've had this same problem and solved it by deleting just the extensions.rdf file, like our anonymous friend suggested on the last comment.

I'm posting this just in case someone arrives to this page looking for a fix: try first to delete the extensions.rdf file, it may work for you and it's easier and faster than ditching away all your config and reinstalling everything.


diddy47 said...

maybe i should make myself a little clearer, the bug is not confined. Depending on how damaged your system is....replacing the .rdf file will be all that is required in some cases, less hustle for you. But for some systems the bug has a lot more other configurations involved that replacing the .rdf will not solve the problem.It would take too long to identify a secondary affected file/config, the only way to get rid of it promptly is to remove all configuration files. Replacing the .rdf without removing the secondary affected configurations means that the new .rdf will become affected soon after its created and the same problem will reappear. NO reinstall of Firefox is required

Anonymous said...

Firefox comes with a profile manager, which allows you to create a second profile without deleting the original one. Even if it will take too long to determine which files are at fault, there's no reason to have to lose all bookmarks and passwords etc.

diddy47 said...

there are a lot of ways to preserve bookmarks and passwords and preferences. one is using FEBE and CLEO. One click restores are an option with these extensions. These extensions exist because siuations like this can happen.

Even creating a seconday profile alone does not mean the problem profile is gone. It's just that you are no longer using it

Anonymous said...

i think it should be mentioned that security programs like thread fire could cause these error. deactivation of these progs during extension installation may help!

Anonymous said...

Yes,I too followed those tips but the problem pops up again after few days. At last I followed these steps as suggested by Empowered SEO and it worked for me. See here
This is one of the option that one can try but the success ratio will depend on the user's problem. Still give it a try, it might help.

Anonymous said...

had the same problem trying to download google toolbar.after i found what i had to go thruogh to install it,i decided i might do more damage trying to get it.i think vista stinks lol........

Anonymous said...

I had a similar problem when I used mozbackup to migrate my Firefox profile from XP 32-bit to W7 Pro x64. I'm glad I found this entry, because the fix for me was as simple as removing the problem add-ons and deleting the extensions.rdf from my profile. After restarting Firefox, I was able to reinstall Foxyproxy, Flashblock (thank God) and IETab. My profile, bookmarks, etc. were untouched.