Invisible minimised Dock icons
Why have the preview icons of minimised apps vanish in the dock?
When you click on the icon, the window appears. Minimising restores the preview.
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RichTeaBisquits wrote:
Why have the preview icons of minimised apps vanish in the dock?
When you click on the icon, the window appears. Minimising restores the preview.
https://discussions.apple.com/content/attachment/475671d9-5a33-4409-a8d6-c7b60870589c
hmmm...If you are using a third party DOCK app— try uninstalling it...
To trouble shoot further you can:
—SafeBoot How to use safe mode on your Mac - Apple Support
Takes a bit longer to get to the login screen, does a quick disk repair before it fully boots up, and certain system caches get cleared and rebuilt, including dynamic loader cache, etc.
Login and test. Reboot as normal and test. Caches get rebuilt automatically.
In Safe mode third party system modifications and system accelerations are disabled, it removes malware, etc hampering smooth operation, however a reboot will put it back to normal mode.
This test will tell you if third party interference; extensions etc are not loaded in safe boot mode.
—Test issue in another user (or guest user) account Set up users, guests, and groups on Mac - Apple Support
This will tell you if it a universal issue or isolated to your user/admin account.
Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus
all known to cause issues on the macOS