How to update to 10.8.6?

Thank you, Varjak and Thank you, Allan.

Unfortunately, after downloading Maverick overnight, I get the message from OS X Mavericks: 1 Incompatible Update. iPHoto version 9.5...(etc) and it says "Requires OS X v10.9.

So I'm still flummoxed.

I tried to run the installer. But it won't let me.

On the page 'Select the disk where you want to install OS X' I have MacIntosh HD ... but a drop down says "This disk is used for Time Machine backups. (It is listed as 999.99 GM total / 59.7 GM available).

I also have a 1TB external hard drive partioned in half with with Super Duper (500.1 GM total, 8 KB available) -- which does not work now -- and time Machine 499.83 GB total, 42.57 GM available.

So I guess my question is ... can I prevent the MacIntosh HD from accepting Time Machine (leaving that for the external HD)?

About This Mac tells me that 10.8.5 is running.

You know, I've been reading about major problems with Maverick if I want to use Apple Mail with gmail accounts. Which I do.

So ... I think I'll just hold off on further attempts to load the Maverick.

I'm still stuck, though, with Super Duper unable to run. I've re-partitioned the external HD to 900 GB for Super Duper. I ran it for hours ... and discovered it needs 950 GBs!