The title says it all: How stable is Sierra as a development platform. Currently we're developing for OS X 10.6 through Sierra, and Sierra seems to have a fair number of problems. Here's what I've seen so far on an official release (i.e. non-development version) of the OS: On a multiboot system a non-development install of Sierra isn't visible on as boot drive on Mavericks or earlier. When attempting to use csrutil to enable/disable SIP, it sometimes locks up the system. Some drives aren't seen or they drop out for no reason. No boot drives on a USB hub won't show up for minutes. Shutdown often locks up. Attempting to boot into the development release of the OS using System Preferences locks up stating it can't update the boot caches. The only way to circumvent this is to force quit System Preferences, reboot, and hold down the "Alt" key when booting to see the development version of Sierra. Interestingly, a Mavericks install can see, select, and allow the system to reboot into the development version of Sierra, but as I said before, it doesn't see the "official release" version at all. My question is simple enough: can Sierra be trusted at all as a development platform?