Of course I was excited to see the new Sierra OS upgrade ready to download and I went ahead. First problem was a warning that the "installer helper" whatever, failed to work. And then things went really bad. Would not start, would just partially load and then go black. Reset PRAM etc...got the Disk Utilities app saying I would need to erase main hard drive (yikes! 1 TB drive of stuff!) Long story short my super powerful 16 month old 32 GB RAM iMac is now a paper weight at the Mac hospital. Warning: BACK UP before trying out Sierra, or even better WAIT! A bit until the fixes are made.
