"Mavericks cannot be installed on this computer," bs!

Your iMac is too old. In order to install Mavericks you must have at least a mid 2007 or newer iMac. Yours is a 2006 model. You can upgrade to 10.7.5 lion http://store.apple.com/us/product/D6106Z/A/os-x-lion

Sorry, but your iMac is too old to install Mavericks.

• iMac (Mid-2007 or later)
• MacBook (13-inch Aluminum, Late 2008), (13-inch, Early 2009 or later)
• MacBook Pro (13-inch, Mid-2009 or later),
• MacBook Pro (15-inch or 17-inch, Mid/Late 2007 or later)
• MacBook Air (Late 2008 or later)
• Mac mini (Early 2009 or later)
• Mac Pro (Early 2008 or later)
• Xserve (Early 2009)

Your Mac also needs:

• OS X Mountain Lion, Lion, or Snow Leopard v10.6.8 already installed
• 2 GB or more of memory
• 8 GB or more of available space

If you wish, you can upgrade to OS X 10.7 Lion

OS X Lion system requirements

To use Lion, make sure your computer has the following:

• An Intel Core 2 Duo, Core i3, Core i5, Core i7, or Xeon processor
• Mac OS X v10.6.6 or later to install via the Mac App Store (v10.6.8 recommended).
• 7 GB of available disk space
• 2 GB of RAM

Purchase an install code for OS X 10.7 Lion here.

http://store.apple.com/us/product/D6106Z/A/os-x-lion

It would be very prudent to create a backup of your system and important data before embarking on a major systems upgrade.

Good Luck!

With regards to iMacs, the model identifier needs to be iMac7,1 or newer; an iMac6,1 is a 2006 model.

(106201)

To find out info about your system,

Click on the Apple symbol in the upper left of the OS X main menu bar. A drop down menu appears.

Click About this Mac. A smaller popup window appears. This gives you basic info like what version of OS X your iMac is running, the speed of your iMac's CPU and how much RAM is installed.

Click on the button that says More Info. A larger window appears giving you a complete overview of your iMac's hardware specs.

http://www.apple.com/osx/specs/ and http://www.everymac.com/systems/apple/imac/specs/imac-core-2-duo-2.16-24-inch-sp ecs.html

You have to meet all the upgrade requirements, not just some. Just like windows.

devinnity wrote:

Also, is just backing up via Time Machine enough?

No.

TIme Machine doesn't make a backup of your system OS and doesn't t create a bootable system you can boot up to.

You would need to purchase another external hard drive (preferably a FireWire 800 connected drive) and use a data cloning app like CarbonCopyCloner or SuperDuper to create a complete duplicate (clone) and bootable copy of your entire Mac's internal hard drive onto this new external drive.

That is THE best backup when doing a major systems upgrade.