Before upgrading to Thunderbird 1.5, it's important to uninstall Thunderbird 1.0x first. Normally, you would not need to uninstall a previous version, but in this case, Thunderbird 1.5 expects an empty Program Files folder during its installation. Failure to uninstall a previous version of Thunderbird may result in the newer version not working properly.
Follow this two-step process, then return to the Thunderbird 1.5 Setup page to continue with installation.
Step 1: Backup your existing profile
Follow these instructions http://www.lehigh.edu/computing/docs/mailbackup/locations.htm to backup your entire profile, which includes address books, local mail, and user settings.
Step 2: Uninstall Thunderbird v1.0x
Open the Control Panel, double-click Add/Remove Programs and locate and select Mozilla Thunderbird 1.0.x in the list. Click the Change/Remove button.
When asked if you want to completely remove Mozilla Thunderbird and all of its components, click Yes.
When the unistallation finishes, close the Control Panel
Return to the Thunderbird 1.5 Setup page and continue with Installing Thunderbird.
kmm3, Last updated: February 22, 2006