The date/time when the OS is installed I just wonder if there are any ways to check the date and time when the Mac OS X was installed.

I guess the system must store the information of this type somewhere, but I don't know how to mine it.

In my case, my MacBook Pro was stolen. When I found it 10 days later, the hard disk had been repartitioned and it had been installed with a fresh Yosemite version.

Now that it turns out that if I know the time/date the Yosemite was installed, I may be able to identify who is the thief.

Cheers,
I have found the answer to my question in this post at the macrumors.com forum. 


  In the System Information application (Apple menu, hold option key, and the first item changes from "About this Mac" to "System Information"), look under the Installations tab. The exact time and date of the OS X install will be listed there.