hello zork, firefox 17 is being released today.

when you're having problems accessing the addons-manager, the files in your profile folder that store the information about your extensions might have become corrupted. please go to firefox > help > troubleshooting information > profile - show folder... then windows explorer should open up your profile folder. in there look for the files named extensions.ini, extensions.sqlite, extensions.sqlite-journal (and in some cases also extensions.txt, extensions.rdf). delete or rename those files and quit firefox, they will be regenerated the next time you launch firefox.

als see https://support.mozilla.org/en-US/kb/Unable%20to%20install%20add-ons#w_co...

Post deleted.

(Reason: originally this was a reformatted and easier to read version of my OP. Then I realised I could edit posts, and so I reformatted my OP and deleted the text in this post.)

Thanks madperson, I'll try that

Firefox 17.0 has been released. You can get it

• by using Help > About Firefox > Check for Updates
• or the full installer at https://www.mozilla.org/en-US/firefox/all.html

Add-ons Manager
I can confirm that neither of the following works after updating to Firefox 17.0. No new tab opens with the Add-ons Manager:

• Firefox button (or Tools) > Add-ons
• Tools > Add-ons

A workaround:

1. Open a new tab
2. In the address bar, type about:addons

Troulbeshooting Information
I can also confirm the following does not work. No new tab opens with Troubleshooting Information:

• Help > Troubleshooting Information

A workaround:

1. Open a new tab
2. In the address bar, type about:support

Other - You should check your Plugins and update as needed

1. Check your Plugins - https://www.mozilla.org/en-US/plugincheck/
2. Shockwave Flash 11.4 r402
   • https://support.mozilla.org/en-US/kb/keep-flash-up-to-date-and-troubleshoot-problems
   • https://support.mozilla.org/en-US/kb/install-flash-plugin-view-videos-animations-games
3. VLC media player Web Plugin 2.0.0
   • Download, save, close all browsers, run the installer you just downloaded. Update here - http://www.videolan.org/index.html
4. Adobe PDF Plug-In For Firefox and Netscape 10.1.2
   • https://support.mozilla.org/en-US/kb/use-adobe-reader-plugin-view-or-download-pdf-files
5. Adobe Shockwave for Director Netscape plug-in, version 11.6.3.633
   • http://kb.mozillazine.org/Shockwave
   • Download, save, close all browsers, run the installer you just downloaded - http://get.adobe.com/shockwave/

Thanks TheOldFox.

These also do not work:

• Help > Firefox Help
• Help >Troubleshooting information (as mentioned)
• Help > Submit Feedback...

Confirmed.

Help workaround - https://support.mozilla.org/en-US/products/firefox

Feedback workaround - https://input.mozilla.org/en-US/feedback

can you try to replicate this behaviour when you launch firefox in safe mode once? if not, maybe an addon is interfering here...

Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems

madperson:

Confirmed your suspicion that an Extension is causing the problem. Now to find which one.

Thanks madperson. I tried your 1st post (it started "hello zork, firefox 17 is being released today....") I deleted all extensions.* files that were present:

• extensions.ini
• extensions.sqlite

Then started Firefox, (which then opened one tab per extension asking me if I wanted to install it). But unfortunately this did not fix the problem.

Tab Mix Plus 0.4.0.3 is the culprit

I added the addons 1 at a time until something broke FF, and it was Tab Mix Plus 0.4.0.3 that broke it.

It's a bit weird that I still seem to have the CTRL+TAB behaviour of Tab Mix Plus even though it is disabled. Specifically CTRL+TAB switches to the last used tab, and does not cycle through tab 1, tab 2, etc.

Also odd is that Tab Mix Plus 0.4.0.3 is available in the list of add ons that work with 17.0.

Can someone else confirm that Tab Mix Plus 0.4.0.3 breaks FF?

This is weird.

The "Warn me when closing multiple tabs" option no longer works. If I open several tabs then close FF, I get no warning.

It's as though maybe Tab Mix Plus has not been completely disabled and is still handling some things like CTRL+TAB, and some other options.

Could this be happening?

Zork:

TabMix Plus is the culprit. I installed the latest TabMix Plus development build 0.4.0.4pre.120724a from their forum and the problem is fixed. Release date for version 0.4.0.4 is not established.

• NOTE from the "Development Channel" section at the bottom of the TabMix Plus add-on page - The Development Channel lets you test an experimental new version of this add-on before it's released to the general public. Once you install the development version, you will continue to get updates from this channel. To stop receiving development updates, reinstall the default version from the link above.
• Link to latest development build (click on the blue "Dev-Build" in the first post to initiate installation) - http://tmp.garyr.net/forum/viewtopic.php?f=3&t=15740

Thanks TheOldFox.

1. can I trust a dev build as it has not been reviewed?

2. is it possible that part of Tab Mix Plus is still installed in FF? (See my last 2 posts) If so, how can I remove it?

Thanks

1. Yes you can trust the development builds on TabMix Plus. I used the development builds on TMP exclusively for over a year until it caused me some confusion when answering questions on the Firefox forum. Check the add-on page for TMP ( https://addons.mozilla.org/en-US/firefox/addon/tab-mix-plus/ ) in a few days to see if version 0.4.0.4 is there and install it without uninstalling the dev-build.
2. TMP, as with most extensions, leaves behind some about:config items when it is uninstalled and/or disabled, that may continue to affect Firefox behavior.
   • When uninstalling an extension, I usually check the prefs.js file in the Profile folder for remnant config entries (with Firefox closed) and edit them out with a pure text editor like Notepad (installed by Windows by default). Just be sure to check that after the edited prefs.js file is saved that some file name extension like .txt was not added to the file name; it must be prefs.js only..
   • I then restart Firefox and check in about:config to be sure that all items for that extension.???? are no longer there.

Thanks TheOldFox.

1. how can "extension.<app>.*" settings in about:config affect FF if <app> has been removed/disabled?
2. In your "Other - Yous should check your Plugins and update as needed ..." post above, how did you know which plugins I've got installed ?!?!

1. The operative word in my reply was "may". Extensions that set "user set" config options may conflict with other extensions that set a similar option. Besides, wouldn't you rather keep your config file clean?
2. Click on "More system details" to the right of your original question for a display of information sent with your original question (that includes the "enabled" Plugins). Some users blank out the "guess" made by the software on this forum; I wish they would not as it does not give us an opportunity to inform them that they need to update Plugins containing security issues.

Please select a reply from those above that solved or helped to solve your original question. That will help other users find a solution with the same problem.

TheOldFox and madperson - thank you for helping me with this problem.