Get Blog This Plugin Working With Firefox 2.0

The Windows Live Writer Blog This extension for Firefox isn’t currently compatible with Firefox 2.0.  However, it is possible to get the two to work together if you are willing to manually edit Firefox’s version checking feature.

If you have not installed the Blog This extension yet, follow these steps.

1. Download the Blog This installer using the link above.
2. Close Firefox.
3. Run the Blog This installer.
4. Without starting Firefox, open the following file in Notepad: C:\Program Files\Windows Live Writer\BlogThis\Mozilla Firefox\install.rdf
5. Change <em:maxVersion>2.0b2</em:maxVersion> to <em:maxVersion>2.0+</em:maxVersion>. ^[1]
6. Start Firefox.

If you have already installed the Blog This extension, follow these steps.

1. Uninstall the Blog This extension (you can only do this from Add/Remove Programs, not from within Firefox).
2. Close all Firefox windows, start Firefox again, close Firefox again. (Important!)
3. Reinstall the Blog This extension.
4. Follow the above instructions starting from Step 4.
5. Without starting Firefox, open the following file in Notepad: C:\Program Files\Windows Live Writer\BlogThis\Mozilla Firefox\install.rdf
6. Change <em:maxVersion>2.0b2</em:maxVersion> to <em:maxVersion>2.0+</em:maxVersion>.  ^[1]
7. Start Firefox.
8. If the toolbar does not display the Blog This button then right-click the toolbar, select “Customize…”, and drag the Blog This icon from the palette onto the toolbar.

I followed the steps and it worked without any problems. 

^[1] Note, set the maxVersion to 2.0+ no matter what.  It may read 2.0b2.* for you.  No problem.  Just update.

Source: Using WLW Blog This with Firefox 2.0 « whateverblog.