If the installer doesn't open automatically, open it manually.
Install Mirra for Windows 2.2 (Full)
Seagate provides two versions of the Mirra for Windows 2.2 installer. If you do not know if Microsoft .NET 1.1 SP1 is present on your computer, download and run this file.
Follow the installer instructions to complete the installation.
Restart your computer after the installation is complete.