To avoid incompatibility problem with previous versions, the Mozilla installer will prompt you to delete the install directory if it is not empty. Answer NO if you put your profile or other personal files in the install directory, otherwise the files will be deleted. Users who put profiles in the default location are not affected.
See the profile FAQ for help on backing up your profiles.
These release notes describe system requirements, installation instructions, and known issues for Mozilla 1.5 RC-1. These various notes are updated when we receive feedback, so please check back for new information. Consult our releases page to download the source and the latest version of Mozilla for your platform.