Why can't I upgrade to yosemite? I'm currently running snow leopard on my white macbook.

Question

Why can't I upgrade to yosemite? I'm currently running snow leopard on my white macbook.

Answer 1

White MacBooks are NOT eligible to upgrade to either 10.8 Mounain Lion, 10.9 Mavericks or 10.10 Yosemite.
You maybe able to upgrade your white MacBook 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
You can purchase a OS X 10.7 Download code here.
http://store.apple.com/us/product/D6106Z/A/os-x-lion
Before embarking on a major OS upgrade, it would be wise, advisable and very prudent if you backup your current system to an external connected and Mac formatted Flash drive OR externally connected USB, Thunderbolt or FireWire 800, Mac formatted hard drive. Then, use either OS X Time Machine app to backup your entire system to the external drive OR purchase, install and use a data cloning app, like CarbonCopyCloner or SuperDuper, to make an exact and bootable copy (clone) of your entire Mac's internal hard drive. This step is really needed in case something goes wrong with the install of the new OS or you simply do not like the new OS, you have a very easy way/procedure to return your Mac to its former working state.
Next,
If you run any older Mac software from the earlier PowerPC Macs, then none of this software will work with the newer OS X versions (10.7 and onward). OS X Snow Leopard had a magical and invisible PowerPC emulation application, called Rosetta, that worked seamlessly in the background that still allowed older PowerPC coded software to still operate in a Intel CPU Mac.
The use of Rosetta ended with OS X Snow Leopard as the Rosetta application was licensed to Apple, from a software company called Transitive, which got bought out, I believe, by IBM and Appe  could no longer secure their rights to continue to use Rosetta in later versions of OS X.
So, you would need to check to see if you have software on your Mac that maybe older than, say, 2006 or older.
Also, check for app compatibilty  here.
http://roaringapps.com/
If you have any commercial antivirus installed and/or hard drive cleaning apps installed on your Mac, like MacKeeper, CleanMyMac, TuneUpMyMac, MacCleanse, etc. now would be a good time to completely uninstall this apps by doing a Google search to learn how to properly uninstall these types of apps.
These types of apps will only cause your Mac issues later after the install of the new OS X version and you will have to completely uninstall these types of apps later.
Once you have determined all of this, you should be able download OS X 10.7 Luon from the Mac App Store icon in the OS X Dock and then login to the Mac App Store using your Apple ID and password.
You can then begin the download and installation process by using the paid download code to Download and install OS X 10.7 Lion rom the Mac App Store.
Good Luck!