missing sidebar icons in Safari

In system preferences > if the position of the dock is set as left , you must uncheck the box of automatically hide and show the dock so that icons will be shown in the dock that is kept on left , and if you dragged and dropped some of the icons into the centre of the desktop ( and they vanished with a poof sound ) , open launchpad and drag and drop the icons / apps again in the dock to be visible and saved .

I have a similar problem—on any given day in the last couple of weeks, several app icons do not appear correctly, and it happens to different apps on different days; instead a generic icon appears. In the image, those two apps that look like a piece of paper with tools are supposed to be the icons for System Prefs and iTunes.

Try doing a Dock restart using the following Terminal command:

killall Dock

Log out/in and test. If that doesn’t work, you need to look in your user Library/Application Support/Dock for the .db. Use the Finder “Go To Folder” command. Enter ~/Library/Application Support/Dock. Move the .db to your desktop.

Then try a dock reset.

Applications/Utilities/Terminal enter the command

killall Dock

Log out/in test. If it works okay, delete the .db from the desktop.

If the Dock is the same, return the .db to where you got them from, overwriting the newer ones.

If you prefer to make your user library permanently visible, go to Finder and select your user/home folder. With that Finder window as the front window, either select Finder/View/Show View options or go command - J. When the View options opens, check ’Show Library Folder’. That should make your user library folder visible in your user/home folder. Learned from leonie.

Run safe mode Use safe mode to isolate issues with your Mac - Apple Support

and NVRAM / PRAM How to reset NVRAM on your Mac - Apple Support

The Bookmarks Sidebar? Try clicking on the links to load them.