• Firefox 4 versions and later do not run on a PowerPC Mac.
• Firefox 4 and later require at least OS X 10.5 and an Intel Mac.
• http://www.mozilla.com/firefox/6.0/system-requirements/

For an unofficial Firefox 4 compatible version (TenFourFox) that runs on PowerPC Macs with OS X 10.4.11 or OS X 10.5.8 you can look at:

• http://www.floodgap.com/software/tenfourfox/
• http://code.google.com/p/tenfourfox/

Firefox 3.6.x (Mac OS X 10.4 and later) can be found here:

• http://www.mozilla.com/en-US/firefox/all-older.html
• http://www.mozilla.com/firefox/3.6/system-requirements/

Thanks I realise that it won't run on non Intel. However it is trying to download update. I can't stop the 'automatic download' it has been trying to download for what seems forever. I've gone to Preferences and removed the rick in Automatically chec,k for updates to Firefox and removed the tick from Automatically download and install the updates but it seems to be stuck in a loop trying to download an update that won't run on my Mac. Any suggestions appreciated.

If files already have been downloaded then you need to remove the files in the updates and updates/0 folder in the Firefox installation folder. You can delete active-update.xml and updates.xml as well if present.

• http://kb.mozillazine.org/Installation_directory

Thanks. That seems to have fixed it.