Brian Wilson, a founder of cloud storage service BackBlaze, writes in a blog post: Moving over to a 64-bit OS allows your laptop to run BOTH the old compatible 32-bit processes and also the new 64-bit processes. In other words, there is zero downside (and there are gigantic upsides). Because there is zero downside, the first time it could, Apple shipped with 64-bit OS support. Apple did not give customers the option of "turning off all 64-bit programs." Apple first shipped 64-bit support in OS X 10.6 Snow Leopard in 2009. This was so successful that Apple shipped all future Operating Systems configured to support both 64-bit and 32-bit processes. All of them. But let's contrast the Apple approach with that of Microsoft. Microsoft offers a 64-bit OS in Windows 10 that runs all 64-bit and all 32-bit programs. This is a valid choice of an Operating System. The problem is Microsoft ALSO gives customers the option to install 32-bit Windows 10 which will not run 64-bit programs. That's crazy. Another advantage of the 64-bit version of Windows is security. There are a variety of security features such as ASLR (Address Space Layout Randomization) that work best in 64-bits. The 32-bit version is inherently less secure. By choosing 32-bit Windows 10 a customer is literally choosing a lower performance, LOWER SECURITY, Operating System that is artificially hobbled to not run all software. My problem is this: Backblaze, like any good technology vendor, wants to be easy to use and friendly. In this case, that means we need to quietly, invisibly, continue to support BOTH the 32-bit and the 64-bit versions of every Microsoft OS they release. And we'll probably need to do this for at least 5 years AFTER Microsoft officially retires the 32-bit only version of their operating system.