On boot, iMac Apple logo blinks red after update to Mac OS Sierra

My brand new 21.5 Retina was bought in august....it blipped red once last week on startup...and things seemed to be running fine. When I tried to install the latest bug fix, it bricked my system. Starts up just fine, chimes...then turns black, back on, blips red...then looks like a corrupted spinny wheel of rainbow colors for a couple seconds...then goes black. It will turn on in recovery mode, but not safe mode. I ran disk utility....reset PRAM blah blah blah....nothing. I have an appointment on saturday....and this thread is not helping my confidence...Remember when it was so exciting to get an upgrade? Now, straight anxiety.

To all IMAC FANS of late running Sierra. Why would APPLE put Sierra out on the market to cause so much problems. Are they starting to slip? When running a business , if this type of a failure occurred I would have to overhaul staff and techniques. What are they doing? I do not know what a good running APPLE feels like. I like the system but not the results. !! GET THIS PROBLEM FIXED OR REPLACE. ENOUGH IS ENOUGH.

So, I tookmy imac to the Apple store on saturday....and something seemed to work...though, it blows my mind. The initial clean install of seirra wouldn't work....but going back to el capitan did. The guy I worked with seems to think the problem has to do with the 2TB Fusion drive in the imac.....something about breaking it apart...and sierra not being able to put it back together. I don't know that much about fusion drives...but that might be a reason...and might be the common denominator in this thread. So, for now....I'm not upgrading back to Sierra....I'm staying with El Capitan for at least 6 months. Why would anyone release an update like that? Now I need to disable the annoying...."DO YOU WANT TO UPGRADE?" notification.

Alicia and EVERYBODY ELSE THERE IS NOTHING WRONG WITH ANY OF YOUR COMPONENTS IN "EL CAPITAN."ONLY IN "SIERRA". I ALSO ARE DEBATING TO LEAVE "SIERRA" AND GO BACK TO THE FUTURE WITH

EL CAPITAN" UNTIL THEY GET THIS FIXED." Frequently Visited Sites does not work properly. I only got one site to show, that is it. I don't have a rotating wheel at shut down either. ??

I seriously doubt that Apple is ever going to be able to fix this problem for because it is most likely a problem with your Mac. Please download and install EtreCheck from http://etrecheck.com/

Run it and post the report here.

Woow! So i should go back and demand a new unit then. Before warranty is out. Mine is not even 3 months old.

Asked at the local store and they just told me its of no significant matter and should be solved next upgrade.

But then what if not and by then my warranty might be out...

I have a late 2015 imac 21" retina that I purchased three months ago. I don't have a fusion drive. I upgraded to Sierra and immediately started getting that red box on startup. I was hoping the update that came out at the end of October would fix it (along with other issues with Sierra) but it is still there. I am glad I am not the only one experiencing this issue!

I called the support line to address other issues with Sierra. I am having trouble dragging and copying songs from itunes to a USB thumb drive. This is an issue I never had before updating to Sierra. I casually mentioned the red box issue and the support team at Apple claims they never heard of the issue before. Yeah right!!!!

Yep, same issue here, same setup. I had to return one iMac in the first week I had it, because it locked up while working in Photoshop Elements—the screen went black and it would not restart. I took it to a genius bar in Boulder CO, and they advised me to return the computer and ordered a new one. This one is doing the same thing in startup, but after lengthy consultations with Apple Help, I was advised that it is a purely cosmetic issue that Apple is working on. So far so good with this one, but I have not yet launched Photoshop Elements and I'm a little hesitant to do so. I would love to hear form anyone else who had a problem with Photoshop Elements.

The people at the genius bar had never heard of it, and when I called Apple Support, the first person I talked to had not heard of it before, either. She consulted with someone at length, and when she came back online said it was a cosmetic issue that Apple is working on.

Same here. I talked to someone at apple support last week. He said they are fully aware of the red box and we're working on it. He said it was just a cosmetic issue. I really don't care about bugs as long as they admit there is an issue and tell me they will fix it.

I told apple support that we all have the same iMac model. It seems to be all 4K late 2015 models so maybe they have a seperate version of sierra for different models. I figured this info may help them figure out the problem.

I have the same issue as well!! Bought my 21" 4k iMac this past May with EL Capitan installed on it, and everything ran perfectly. Went to install Sierra as the new O.S two weekends ago, and now everytime I go on my iMac I'm finding more and more things going wrong. The first thing I noticed was, two out of five times when I go put my computer into sleep mode it will hang onto that black screen that's still kind of lit, before turning off into the completely black screen. The second thing I noticed was with my old O.S (EL Capitan) you use to have click on the mouse to wake it up from sleep mode, where as now if I breathe on the mouse to hard it will wake up. The third thing I noticed was itunes will periodically close unexpectedly. The forth thing I noticed was I'm getting the beach ball for no reason at times. The fifth thing I noticed was the red/green blinking Apple logo upon restart or cold boot. The loading bar will get about 3/4 of the way and then the Apple logo will do this weird red/green millisecond flash.....*** APPLE!!!! Anyways, it looks like for now since Apple doesn't look like they care all that much seeing that this O.S has been out for sometime to put a patch on it, is to either live with it, or revert back to EL Capitan in having to reinstall all your programs. :/

Call apple support. Tell them you want to clear your cache and then reinstall the operating system. You hit control + R or something while you boot up. It will give you like 4 options. You want to pick the option that reinstalls the operating system. It took me two hours to complete. Then the computer boots up and asked me a few questions like do I want to sign into iCloud. Once the computer booted up all my files and programs were still there. The computer looked exactly like I left it. It is less buggy now. It runs fast! You need to do it because it will help. Just call apple support but don't go with the first tech. Tell him you want to speak with a senior advisor. The senior advisor is the one that had the brains to suggest I reinstall the operating system.

Ya I called Apple last night about these issues. So as the red logo boot screen, the sleep mode issues and iTunes occasionally crashing won't break the iMac, it's still none the less very frustrating. What is the most frustrating is that if the Apple techs apparently read these forms why has it not been commented on by them nor a patch put out. I know I could redo my iMac but I'm not wasting a whole day doing so on an operating system that is not beta and should have been tested on all new models. Apple fix this as it's looking to be wide spread on late 2015 4k iMacs!!!!

The red logo boot screen is a cosmetic issue that Apple has acknowledged.

Reinstalling the operating system is stupid easy. You push a couple buttons and let it do its thing. Come back to it in a couple hours and you are done! You don't lose any data and you don't have to reinstall your programs. These things are machines and require a little bit of maintenance. If you want to update your computer and keep it running fast and efficient, you are going to have to do some maintenance. This is the price you pay. When you buy a car you don't complain about having to service it with oil changes and brakes.