I've got a very weak signal spy shop birmingham If price isn’t a barrier to an upgrade for either platform, why isn’t the number 100 percent? The obvious reason is that users are rightfully gun-shy of big upgrades like this. The upgrade process is never guaranteed to be successful, even on the much more tightly controlled Apple hardware platform. In Apple’s case, Mavericks came with an assortment of bugs and issues that had even Apple loyalists urging a wait-and-see attitude.