Sometimes, when switching applications then back to InDesign, some of the panels are turned off. One that's particularly annoying is the Swatches panel. It doesn't always do it but when it does it's really annoying having to open it back up again.
Resetting InDesign preferences doesn't fix it.
This only seems to affect one Mac that's running El Capitan. We have others that are also on the same version of OS and same version of InDesign that don't do this.
Steve Edwards commented
I've since updated my Mac to HIgh Sierra. It seems to have fixed the missing panels bug but sometimes now when I click on say Swatches (when it's collapsed), it doesn't do anything and neither do any of the other panels that are collapsed. It needs and InDesign (and sometimes complete) restart before it will expand them.
I'm having the same problem--the computer goes to sleep or i restart indesign and all of my panels are gone. I have to manually open each panel, and then once reset, they don't seem to be working properly! They won't open to the left from the collapsed setting.
Logan Johnson commented
I have a similar issue where the Swatch panel turns off at random. It seems to happen to me most when I use Tab to hide the panels to view the layout. When I press tab again sometimes the panel is gone.
Easily reactivated in the windows menu... but a pain.
I'm using High-Sierra and the latest InDesign CC version.