To prevent unauthorized usage, the update file has been password protected. The password is the 19th Glossary term defined in the Hard Disk SpeedTools User's Guide. Additionally, the password/term must be typed in using EXACTLY as it appears (including Capital and lower case letters). To point you in the right direction, the 1st term to appear in the glossary is "Address", the 2nd term is "Apple Menu Item", the 3rd is "ATA" and so on...
The update file is compressed. To open it, double click on the "HDST 2.1.sea" file. Type in the password as instructed above and that's it.
Additional Note: We frequently rotate which Glossary term is used as the password. So, please review the attached "Read Me" document again should you download a future Hard Disk SpeedTools version updater.