Starting and shutting down extremely slowly

Do you have a question, or did you just want to rant? You are not communicating to Apple on these forums, they do not read them or participate in them. We are all end users like yourself, people volunteering their time.

Hi,

I had the same issue once with my Mac Mini after "Upgrading". SMC reset did not help, NPRAM reset did not help. Tricks, smoke and mirrors did not help even after pulling up countless OS and HD stats. So I did what anyone would do...

Backed up my personal Data to External HD. Shutdown. Unplugged everything that did not come with my Mac (USB Sticks, External HD's, Printer, etc.)

Powered up into Recovery {command+R} Erased the Macintosh HD in Disk Utility

Install New Copy of OS X. (This will install a New Copy of Yosemite 10.10.5). Re-Setup my Mac like new. It worked! Just don't forget your Login ID's and Passwords for Apple, Router Wi-Fi, etc. This sounds drastic to some but I grew tiresome of the troubleshooting antics and I cut to the chase. Now over a year later, I keep that backup updated just for times like yours. Reinstalling OS X is a cake walk like resetting an iPhone, compared to Windows.

Cheers!!

Ranting on these forums is not acceptable, read the Terms of Use you agreed to. They specifically state:

Post constructive comments and questions. Unless otherwise noted, your Submission should either be a technical support question or a technical support answer. Constructive feedback about product features is welcome as well. If your Submission contains the phrase “I’m sorry for the rant, but…” you are likely in violation of this policy.

Post an EtreCheck report of your system and we can look for obvious issues. Chances are the issue(s) are caused by something you or another user did to the system.

Okay, instead of erasing just the Macintosh HD try this. Make sure only your iMac, Keyboard and Trackpad/ Mouse are present. Nothing else connected.

Boot in Recovery>Disk Utility

Select "APPLE HDD" click on Partition Layout Tab use drop down to make 1 Partition then click Apply

Select the "Untitled" or Untitled 1" disk

Click on Erase Tab and Name it "Macintosh HD" in Security Options raise the slider 1 mark. Then click Erase

This takes a while. This will write zeros across the entire HD in one pass. This will also wipe out the old Disk0 Recovery partition.

Immediately Install New copy of OS X when full erase is complete.

This has helped me in the past. It requires a little patience during the erase. Approx. 1 hour and 10 minutes to write zeros on my 500 GB HD. In the end it's worth it. During the Install of OS X a new Recovery Partition and Data is created. No worries. Just takes time to get to the "Welcome" screen.

Cheers!!