how can i disable switch screen animation in catalina?
yabai + BetterTouchTools
yabai is a window manager for mac. If you want to get rid off all animations completely and move very fast around your computer, then this is the way to do it. It is a command line tool so you will need to pair it with some kind of key mapping or mouse/trackpad mapping utility.
You can use BetterTouchTools to remap your trackpad motions. I used it to map three finger swipe to a yabai command that changes between spaces instantly.
Map &quot;3 Finger Swipe Left&quot; to &quot;Execute Terminal Command (async)&quot; with the command:
/usr/local/bin/yabai -m space --focus next

and &quot;3 Finger Swipe Right&quot; to &quot;Execute Terminal Command (async)&quot; with the command:
/usr/local/bin/yabai -m space --focus prev

disabling most other animations
Unfortunately I haven't found a way to change macos defaults to completely turn of this fade animation but this should speed up most other animations that may be annoying you (or you didn't notice but would be glad to have them disabled).
This link has a pretty good catalog of different options that can be disabled/enabled/changed to speed things up and remove annoyances. Some similar to what you want:
| Command | Description |
| --- | --- |
| defaults write com.apple.dock launchanim -bool false | Don’t animate opening applications from the Dock |
| defaults write com.apple.dock expose-animation-duration -float 0.1 | Speed up Mission Control animations |
| defaults write com.apple.dock mineffect -string &quot;scale&quot; | Change minimize/maximize window effect (faster) |
| defaults write com.apple.dock autohide-delay -float 0 | Remove the auto-hiding Dock delay |
| defaults write com.apple.dock autohide-time-modifier -float 0 | Remove the animation when hiding/showing the Dock |
| defaults write NSGlobalDomain NSWindowResizeTime -float 0.001 | Increase window resize speed for Cocoa applications |
need more speed?
yabai + karabiner
I use Karabiner to configure tab to act as a window managing modifier key if I don't press it alone (i.e. if I don't want to just press tab). Doing this you can resize windows, arrange them, move them to other spaces, and change focus between spaces/windows all with the keyboard. I also have caps lock configured as a modifier key that launches/focuses applications. This way you can go directly to the application you want and use yabai to have it open instantly.
Here is my Karabiner configuration if you want to get more into window management. I mostly use Goku to do my Karabiner configuration because it makes it easy to do complicated mappings.