I recently had occasion to format my iMac's HDD so being confident in the knowledge that I had backed everything up on Time Machine, I inserted the Snow Leopard disc and a short while afterwards my Mac was back to basics.

I THEN connected my external iomega hard drive with my Time Machine backups and began selecting the files etc that I needed. My backups were on average, monthly and went back to June 2010. So far so good. Then, when I tried to restore my address book, I found that the iomega (Time Machine) only goes back to September 2010... all the previous backups have been compressed (including my address book) and I can not get OSX to see the files.

Any ideas on how to decompress the backups on the external hard drive or any other suggestions on how to access the information I need from it will be most welcome.

Thank you