hello, this might happen when firefox is not able to properly save preferences in its profile folder. please try this: Click the menu button and then click help > troubleshooting information > profile folder - "show folder". then a new window will open up. in this window look out for a file named user.js (it might be used to overwrite your custom settings). in case it is present , delete or rename this file and restart firefox afterwards.

for more information and other steps please also see: How to fix preferences that won't save

The user.js file is not listed. There are, however, dozens of files with this name: prefs-8.js (where the '8' changes to a new number on each file. there are 720 files!

please make sure that the original prefs.js isn't write-protected (as it's explained in the article from above) and delete all the consecutive prefs-n.js files.

I do notice that under Extensions on the Troubleshooting page, the Default Tab and the Print pages to PDF are both listed. That's where the problem is coming from. How can I delete those?

Extensions Name Version Enabled ID Default Tab 2.4 true [email protected] Print pages to PDF 0.1.9.3 true [email protected] AVG SafeGuard toolbar 18.1.5.514 false avg@toolbar IDS_SS_NAME IDS_SS_VERSION false {D19CA586-DD6C-4a0a-96F8-14644F340D60} Tube Dimmer 2.6.43 false [email protected]

Awesome. looks to be fixed! Must be a problem that is embedded in the last upgrade. Thanks!, phillipp

Note that your System Details List shows multiple Adobe PDF plugins.

1. Adobe PDF Plug-In For Firefox and Netscape 11.0.06
2. Adobe PDF Plug-In For Firefox and Netscape "9.5.5"

You can find the installation path of all plugins on the about:plugins page.

• http://kb.mozillazine.org/Issues_related_to_plugins#Identifying_installed_plugins

You can open about: pages like the about:plugins page via the location bar (about: is a protocol used to access special built-in pages).