Starting with macOS 10.15, Apple introduced a read-only system volume for system content. In macOS 11 the security was further hardened with the introduction of the signed system volume. This is good for security of course, but makes it harder to change things, for example system application icons. There is a solution though.

First, you must boot into recovery mode. Once in recovery mode, open “Terminal” under “Utilities” in the menu bar and run the following commands to disable system integrity protection and authenticated root:

csrutil disable
csrutil authenticated-root disable

When you have run the commands, reboot and log back in as normal. Run the following Terminal commands to first create a temporary directory, and then to mount your system disk as writeable:

mkdir ~/system_disk
sudo mount -o nobrowse -t apfs $(mount | awk 'NR==1 {print substr($1,1,length($1)-2)}') ~/system_disk

Your disk will appear inside your home folder and will be writeable. After you have made your changes, run the following Terminal command to “bless” it:

sudo bless --mount ~/"disk/System/Library/CoreServices/" --setBoot --create-snapshot

After you have blessed the drive, reboot once again, and then you’re done.

With the release of macOS 11 (Big Sur), Apple introduced a new design language that added more padding throughout the interface. This is what a Finder window looks like on macOS 12 (Monterey) (see the sidebar and the table view):

If you want to restore the old, more compact style used on macOS 10.15 (Catalina) and below, there are two Terminal commands for that. Simply run:

defaults write -g NSSidebarUsesGoldenMetrics -bool FALSE #force a plain style on sidebars globally
defaults write -g NSTableViewCanUseGoldenStyles -bool FALSE #force a plain style on table views globally

And you will get your UI looking like this:

If you wish to enable it only for a certain app, provide the app’s bundle identifier instead of -g. For example, if you wish for the change to apply only in Finder, run:

defaults write com.apple.finder NSSidebarUsesGoldenMetrics -bool FALSE #force a plain style on sidebars in Finder
defaults write com.apple.finder NSTableViewCanUseGoldenStyles -bool FALSE #force a plain style on table views in Finder

To revert back to the default style, just delete the setting:

defaults delete -g NSSidebarUsesGoldenMetrics #delete the sidebar setting globally
defaults delete -g NSTableViewCanUseGoldenStyles #delete the table view setting globally
defaults delete com.apple.finder NSSidebarUsesGoldenMetrics #delete the sidebar setting in Finder
defaults delete com.apple.finder NSTableViewCanUseGoldenStyles #delete the table view setting in Finder

The first Mac OS X version I can remember using was 10.4 (Tiger), and I still love the way it looks. The design changed quite a bit with 10.5 (Leopard), but not necessarily for the worse. The Leopard look is also beautiful in its own right, and I can’t really decide which one I like more.

Starting with 10.7 (Lion) though, Apple started shifting towards a flatter, less colourful look.  The previously detailed and colourful sidebar icons turned grey and monochrome, as did the scrollbars. The colourful toolbar icons, like those in app preference windows, held out all the way until macOS 10.15 (Catalina), when almost everything else had already been flattened. They finally disappeared in macOS 11 (Big Sur), when Apple managed to make macOS look even more lifeless, replacing greys with plain whites and swapping out most interface icons for minimal, monochrome SF Symbols.

Missing the old look, I built two tweaks for macOS 12 that let me control the sidebar and toolbar icons.

Sidebars

This tweak scans the app’s user interface and detects sidebar elements, like the cells that list folders och mailboxes. Once found, it swaps their default icons with custom ones defined in a mapping .plist file that links icon identifiers (like labels, file paths, or SF Symbols) to replacement images. Here is how it looks.

Before:After:

Toolbars

The toolbar tweak works essentially the same way. It scans the toolbar inside the preferences window of apps and swaps their icons according to what is defined in the mapping .plist file. Here is how it looks.

Before:

After:

The “after” screenshots also show a few extra touches from another tweak not detailed here, but essentially it loads the SystemAppearance.car (lifted from macOS 10.14) in order to restore its textures, changes the title bar font to regular, and in Finder it extends the toolbar and status bar.

Homebrew is, in my opinion, an essential package manager for macOS. It greatly simplifies the process of installing and maintaining many different pieces of software. According to Homebrew’s website it “installs the stuff you need that Apple didn’t”.

To begin with, if you don’t already have them, install the Xcode Command Line Tools. Homebrew relies on Xcode Command Line Tools, which include compilers and other essential tools required for Homebrew to work. To install Xcode Command Line Tools, open Terminal in /Applications/Utilities/ and run the following command:

xcode-select --install

Click install and then agree to the license agreement.

Then to install Homebrew itself, run:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

and let it install. After the installation is complete, you can run simply:

brew

to verify that it has been installed correctly.

How do you use Homebrew?

Some commands you can run are:

brew search

This searches for packages available for installation.

brew install

This installs a package.

brew upgrade

This upgrades a package.

brew update

This updates Homebrew itself.

brew uninstall

This uninstalls a package.

brew list

This lists installed packages.

Sometimes, for some reason, certain Mac applications will change a setting, turning off the ability to make a backup of your iPhone in iTunes. If your “Back Up Now” button is greyed out, this might be what has happened to you.

To see if this is the case, open Terminal in /Applications/Utilities/ and run:

defaults read com.apple.iTunes DeviceBackupsDisabled

If the response is 1 or TRUE, then this solution applies to you. To turn on the ablity to back up again, just run:

defaults write com.apple.iTunes DeviceBackupsDisabled 0

and the issue will be resolved.

There is a bug in macOS High Sierra (10.13) which prevents Time Machine backups from completing. If your backups aren’t finishing, then you might have this problem. To see if you do, open up Terminal in /Applications/Utilities/ and run this command

log show --style syslog --predicate 'senderImagePath contains[cd] "TimeMachine"' --info

If you see messages like this:

2018-01-26 13:31:35.269569+0100  localhost backupd[2082]: (TimeMachine) [com.apple.TimeMachine:TMLogError] Failed to unmount disk mounted at '/Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Mac/2018-01-26-133135/MacintoshHD', error: {
    Action = Unmount;
    Target = "file:///Volumes/com.apple.TimeMachine.localsnapshots/Backups.backupdb/Mac/2018-01-24-164749/MacintoshHD";
}

2018-01-26 13:31:35.269970+0100  localhost backupd[2082]: (TimeMachine) [com.apple.TimeMachine:TMLogError] Failed to unmount snapshot: com.apple.TimeMachine.2018-01-24-164749 source: MacintoshHD
2018-01-26 13:31:36.322938+0100  localhost backupd[2082]: (TimeMachine) [com.apple.TimeMachine:TMLogInfo] Backup canceled.

Then it is likely that you have this problem.

To finish a backup, you have to temporarily disable Spotlight. To do this you must first disable SIP (System Integrity Protection). Restart your computer, and once it is booting hold +R to boot into recovery mode. Open the Terminal from “Utilities” in the menu bar and disable SIP through this command:

csrutil disable

Then reboot, and again open Terminal and run this command to disable Spotlight:

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

Complete

Barring other problems, you should be able to finish your backup after this. To enable Spotlight again, run this command:

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.metadata.mds.plist

To enable SIP again, you can either reboot into recovery mode and run:

csrutil enable

or just reset your NVRAM. To reset your NVRAM hold +alt+P+R during boot.

Go to the application in Finder, right-click it, and click “Show package contents”. Go inside the folder “Contents”, there you will find a file called info.plist, which is the file we are going to edit.

First make a backup in case you want to easily revert or if something goes wrong. If you have Xcode, open the file with Xcode, if not, open it with TextEdit. The reason I say TextEdit is because some plaintext editors cannot handle .plist files.

With Xcode

Hover the mouse over any key and click the plus to create a new key. Name it NSUIElement, and change the value to 1.

With TextEdit

Add:

<key>NSUIElement</key>
<string>1</string>


to the second last line, just before </dict> and </plist>

Save the file, and restart the application. It will now run in the background.

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

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

defaults write com.apple.Safari DebugSnapshotsUpdatePolicy -int 2

Then, go to ~/Library/Caches/com.apple.Safari/Webpage 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.