Why cant i upgrade my 17in macbook pro (s/w 10.6.8)to mavericks

Question

why cant i upgrade my 17in macbook pro (s/w 10.6.8)to mavericks?  I do not know what month it was built.  I bought it as a refurbished by Apple a few months ago.

Answer 1

Check that your computer is compatible with Mountain Lion/Mavericks/Yosemite.
To check the model number hold down the option/alt key, go to the Apple menu and select System Information.
iMac (Mid 2007 or newer) model number 7,1 or higher
MacBook (Late 2008 Aluminum, or Early 2009 or newer) model number 5,1 or higher
MacBook Pro (Mid/Late 2007 or newer) model number 3,1 or higher
MacBook Air (Late 2008 or newer) model number 2,1 or higher
Mac mini (Early 2009 or newer) model number 3,1 or higher
Mac Pro (Early 2008 or newer) model number 3,1 or higher
Xserve (Early 2009) model number 3,1 or higher
Your Mac needs:
OS X v10.6.8 or OS X Lion already installed
2 GB or more of memory (More is better - 4 GB minimum seems to be the consensus)
8 GB or more of available space
Check to make sure your applications are compatible. PowerPC applications are no longer supported after 10.6.      
Application Compatibility
Applications Compatibility (2)
Do a backup before installing.
Your iMovie and iPhoto data should be good, but you will have to upgrade the applications.
If you decide the upgrade isn't worth it, you can share Mail, Calendars, and Contacts running Snow Leopard. Based on my experience, I don’t recommend syncing Contacts - created a lot of problems with duplicates. If you have 2 step verification enabled on your Apple ID, you will need to generate an application specific password for Mail, iCal, and Address Book. Apple ID - Manage
Snow Leopard iCloud - Address and iCal
Snow Leopard iCloud –  iCal
Snow Leopard iCloud - Configuring Mail with Mac OS X v10.6 or iOS 4