MacOS Sierra slow? Why? And How to fix?

It is normal if your Mac gets slow after upgrading to MacOS Sierra. Let’s see the following words to see the possible causes and solutions to fix.

Macos Sierra Slow

Macos Sierra SlowIs your mac compatible to run New Mac OS X 10.12 – Sierra?

If your Mac model does not belong the following the MacOS Sierra Compatibility List, you may think about either rolling back to El Capitan, Yosemite or whatever version of OS X you have used without problems before or upgrade the hardware.

  • MacBook Pro (2010 and later)
  • MacBook Air (2010 and later)
  • Mac Mini (2010 and later)
  • Mac Pro (2010 and later)
  • MacBook (Late 2009 and later)
  • iMac (Late 2009 and later)


1. Free up the memory

Here is the key: Free memory = Faster MacOS Sierra.

Cleaning up the entire Hard Drive is the most effective way to speed up your Mac. There is a ton of unnecessary datas such as Caches, logs, apps, widgets, language packs, plugins, hidden trashes, and large files are stored constantly into the HDD. You can handle and clean them up manually, but it takes so much time and you have to repeat the long process frequently that I will give you the specific instruction in this topic soon. I would introduce CleanMyMac 3, the best professional application to clean up your Mac for just couple of minutes.

CleanMyMac - Speed up Macos Sierra slow

Removing duplicates would help to free-up the HDD so much to speed up slow MacOS Sierra effectively. You may want to take a look on How to find and remove duplicate files under Macos Sierra.

How to manually Clean-up the Mac’s HDD under MacOS Sierra?

Utilize the new optimize storage function

According to Apple,  Optimized Storage in macOS Sierra can save space by storing your content in the cloud and making it available on demand. When storage space is needed, files, photos, movies, email attachments, and other files that you seldom use are stored in the cloud automatically.

Free up the mac using optimize storage function

Free up the mac using optimize storage function

To launch this function, Apple Menu –> About this Mac –> Storage –> Mana…

Further more, we can manually clean-up the mac using the following keys:

  • Empty the Trash folder of your MacOS Sierra
  • Remove all un-needed apps
  • Delete log files: From the Finder window, call “Go to folder” function by hold the combination of Command + Shift + G keys, then enter the following direction:


  • Remove data from Download folder
  • Cleanup Mailbox: In Mail, choose Mailbox > Erase Deleted Items > In All Accounts, and Mailbox > Erase Junk Mail
  • Locate and remove large files, which are useless, from your Mac. Click here for specific instruction.
  • Move large files to External Hard Drive

2. Optimize the Disk using Disk Utility

  • Reboot the Mac, keep holding down the ‘command’ + ‘r’ until the Mac is booted into recovery mode
  • From the top menu, Launch Disk Utility > Select the Macintosh HD > Click on First Aid button.
Run First Aid on MacOS Sierra

Run First Aid on MacOS Sierra

3. Clean Off a Cluttered Desktop

You may store tons of files on their desktops, resulting in a very cluttered desktop full of files and folders and other stuff. Don’t do this because this can slow down the Mac’s performance.

Massive desktop causes Sierra slow

Massive desktop causes Sierra slow

Make the Sierra desktop organized will speed up the Mac.

4. Run SMC and PRAM resets on Mac

For further instruction, look at the following topic from Appledigg: How to reset NVRAM/PRAM on Mac

5. Moderate the UI experience

MacOS Sierra concludes great provision of top class fresh looking user interface. The awesome effects such as transparency and heavy app duty will slow down the Sierra OS. To turn off the “heavy effects”: System Preferences –> Accessibility –> Display

Macos Sierra slow

MacOS Sierra slow

Just make sure you check the box for “Reduce motion” and “Reduce transparency”.

6. Managing Startup Items would speed up MacOS Sierra

System Preferences –>  Username –>  Login Items –> Click on the lock symbol at the bottom right conner to be able to manage the login item.

manage login item sierra

Do this perfectly, you fix Sierra slow login.

7. Turning Siri Off

I personally found that My MacOS Sierra runs slower with the Siri in the background. Turn it off, and you see the good results.

System Preferences –> Siri –> Uncheck on Enable Siri

Disable Siri on MacOS Sierra

Disable Siri on MacOS Sierra


Upgrade RAM and attach your Mac computer with an SSD if possible will absolutely speed up your Mac so much.

However, you should follow the guides on Apple support website, and inside of user-upgradeable Macs, the user guide will list the process involved to upgrade the RAM.

Boom! MacOS Sierra slow problem is solved. No more sad days.

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