How to speed up Time Machine backups on macOS 10.12 Sierra

Time Machine is a great tool for backing up your system, but sometimes it can be very slow, in fact by default Time Machine prevents itself from using to much of your processing power. You can turn this off by opening Terminal in /Applications/Utilities and running:

sudo sysctl debug.lowpri_throttle_enabled=0

This will prevent Time Machine from throttling itself. To turn on the throttling again, just run the same command with 1 instead of 0, like this:

sudo sysctl debug.lowpri_throttle_enabled=1

How to use custom thumbnails for Safari Top Sites

First you have to disable thumbnail refreshment, to do that, open Terminal in /Applications/Utilities/ and run:

defaults write DebugSnapshotsUpdatePolicy -int 2

Then, go to ~/Library/Caches/ Previews.

If the user Library folder is hidden, you can access it by pressing Command + Shift + G (⌘⌃G) in Finder, pasting the path in the text field and clicking “Go”.

In that folder you will find jpeg files with 32 character names. Either edit those directly, or copy images to the folder and rename them to whatever the name the different websites’ thumbnails had.

Remember to keep a backup of the files, since they are stored in a cache folder which might be emptied by certain programs or upon installing a new system.

How to enable the startup chime on newer Macs

The classic startup chime has been disabled on newer macs, Late 2016 and on, but it’s not gone and it’s possible to enable it again. Another new feature is automatic boot-up when the lid is opened, which can also be disabled.

To return to the old settings, you have to open Terminal in /Applications/Utilities/ and run two commands.

Here is the command for enabling the startup sound again:

nvram BootAudio=%01

And here is the command for disabling auto-boot:

nvram AutoBoot=%00

After running this, you will have returned to the old settings, however, it is not a permanent change. It is stored in the NVRAM which might be reset every once in a while. There is a solution if you want this to be permanent.

First, open Script Editor in /Applications/Utilities/ and paste this into the document:

do shell script "nvram BootAudio=%01" with administrator privileges
do shell script "nvram AutoBoot=%00" with administrator privileges

Save it as an application wherever you like. Then open System Preferences, search for “Login Items”, open the panel, click the plus under the list of startup applications, navigate to the application that you just created and select it.

Every time you login, the application will automatically launch, enable the startup sound and disable auto-boot, but it will prompt you for your password every time you login. If you want to fix this, you have to edit the /etc/sudoers file. Do not open the file directly, instead run sudo visudo in Terminal. Then add this to the end of the file:

username ALL= NOPASSWD: /usr/sbin/nvram BootAudio=%01
username ALL= NOPASSWD: /usr/sbin/nvram AutoBoot=%00

This will enable you to run these two commands without having to type in your password. Every time you login, the application will automatically launch, enable the startup sound and disable auto-boot.