My Late 2008 Aluminium Macbook has 10.9.5 on it. The update tool offered me Sierra but then predictably told me I can't have it as this Mac is too old. I don't know what the last supported OSX version is for this Mac… is there a way I can get it?
In an ideal world I'd like to do a clean install as this MacBook is full of all kinds of crud I don't want anymore.
Best Answer
The latest OS supported on a Late 2008 Aluminum MacBook is OS X 10.11.6 and can be downloaded from this link which will open in the App Store.
Note that while is starts off saying "This version of OS X El Capitan is for users running OS X Snow Leopard...", it also says...* "This version of El Capitan can also be used on Mac computers that are not compatible with Sierra.".
You can use the instructions in Create a bootable installer for macOS to create a USB Installer to do a clean install of OS X El Capitan.
After creating the USB Installer, you can boot the Mac with it and do a clean install. Make sure you backup anything you do not want to loose before erasing the HDD and installing OS X El Capitian.