OK. So I downloaded the Sierra update, installed it, and right before it was finished, it came up and said that QuickBooks 2013 was placed in an "incompatible" folder. What? It then opened Sierra, and I couldn't open QuickBooks because it keeps coming up with an incompatible message. No warning before I installed. What happened to looking at the apps that I have on my computer and warning me BEFORE it installs the OS. I think somewhere, someplace, somebody, should make it well aware of the apps that are "incompatible" so that we know not to update to the new operating system. I had to add a partition to my hard drive so that I can add the El Capitan operating system back on my hard drive, use command R at start up to boot from my Time Machine, and wait eight hours for the reinstall. 2013 is only two and half years ago (if you bought it in mid-2013), and the software cost almost $300. Way to go Apple and Intuit.