That problem is caused by Norton. There is no good reason for them to micro-manage Firefox 4.0.# security updates and cause this sort of problem for their users. Mozilla very carefully built their numbering system to avoid such problems.

major version dot minor version dot security update - the first two require an update by the developer of the extension, but the last number shouldn't cause a problem.

I try this method & ok:

Actually, the toolbar works fine in Firefox 4.0.1, but it just doesn't know it! Here is the fix. 1) Disable Norton Tamper Protection. 2) Find the file install.rdf dated 4/6/2011 hidden in a subdirectory of a Norton data folder. Open install.rdf in Notepad. Change the maxversion setting from 4.0 to 4.0.1. Save the file. 3) Reenable Norton Tamper Protection. 4) Open Firefox and install the update.

source: http://community.norton.com/t5/Norton-Internet-Security-Norton/Norton-Toolbar-not-compatible-with-FF-4-0-1/td-p/442788/page/2

post by drminer

I was able to roll back to Firefox 3.6.17 and I'm good. To Hell with 4.0.1. Thanks for the input. I'll hold it as a backup. I think Norton and Mozilla should be fixing the problem instead guys like you. Mike

Go to - http://www.mozilla.com/en-US/firefox/all-older.html they offer a long list of Firefox versions to download!

On search for Firefox, select the 'Firefox 4.0.1' heading (not the 'download' section below it). This will then open a new window and on the right hand side is a long list of the Firefox versions back to the original! Take your pick!

Hi kokoyoyok-I tried your suggestion, but could only find an rdf file dated 4-16-2010; I tried changing " 5.*" to "4.0.1" but it wouldn't let me save the new code.

I am using Norton Internet Security 2011. I have same issue with toobar and FF 4.01. I have gone thru all my program files in the Norton directory and can not find an Norton data folder or and an install.rdf folder anywhere. Can you point me to right location.

After looking for file over a 24 hour period I finally found the file after doing an advanced search. My file was dated 5/1 as that was the date I installed. I followed instructions contained in the post above by kokoyoyok and now my toolbar is back. Seems like a simple fix that Norton couldn't have done it and posted as so many now use FireFox.

Thank you! Once I found the right install.rdf file, I changed the max version and my Norton toolbar is right back where it belongs.

I can't find the file install.rdf on my computer. any suggestions where to look I am running Windows 7 64 bit