The new Mac OS X 10.12 called MacOS Sierra may not perform well especially your Mac was made before 2009. Look at our following effective solutions to speed up MacOS Sierra and get it right up to speed again like it used to work with El Capitan, Yosemite or any older OS X versions.

Macos Sierra Slow
Speed up MacOS Sierra

The less Data the Mac carries, the faster MacOS Sierra perform

There is a ton of unnecessary datas which can slow down your Mac such as Caches, logs, apps, widgets, language packs, plugins, hidden trashes, and large files are stored constantly into the HDD. You actually can find 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 below soon.

To be wise, I would introduce CleanMyMac 3, the best professional application to clean up and optimize your Mac system.

CleanMyMac - Speed up Macos Sierra slow

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In another aspect, deleting duplicates would help to free-up the HDD so much to speed up slow MacOS Sierra effectively. We also share downloadable Gemini 2 v2.1.2 Full version in this topic: How to find and remove duplicate files under MacOS Sierra.

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

  • Empty the Trash folder of your MacOS Sierra
  • Get rid of desktop clutter
  • Remove all un-needed apps, especially the heavy games
  • How to remove 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:


  • Delete data from Download folder
  • How to Cleanup Mailbox: In Mail, choose Mailbox > Erase Deleted Items > In All Accounts, and Mailbox > Erase Junk Mail
  • Empty Safari cache: Safari > Reset Safari and check Remove all Website Data
  • 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.

Optimize the Disk using Disk Utility MacOS Sierra

3. Run SMC and PRAM resets on Mac

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

4. Moderate the UI experience

Actually, the new 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

Turn off the heavy effects Sierra OS

5. Turn Off File Vault encryption

File Vault encrypt data you store on your Mac.  It of course uses lots of processor cycles.  To turn it off, Preferences > File Vault tab > Unlock the padlock with your admin password > Turn off File Vault

Turn off File Vault encryption


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! No more sad days, the MacOS Sierra must run faster now.