My new InDesign update 5.1.3 as well as (previous versions 5.x) behaves strange on High Sierra: it launches and then closes with an error. CC connection is active. Once I log out of CC, InDesign works like it should. All other CC apps beside LR Classic work properly as well (LrC requires a logged in user or it won't start).
Is there a way to make InD work properly with an active CC connection? Or maybe a way to downgrade CC (feel like the new version of the CC app is the problem).
Do you actually mean InDesign 15.1.3 which is the latest update to InDesign CC 2020? Have you tried trashing your inDesign preferences? Doing this will revert your InDesign to its defaults but hopefully will clear up any possible corruption you're experiencing.
To do so on a Mac:
The User Library folder in which InDesign’s preferences are stored is hidden by default on most Macintoshes. To access it make sure that InDesign is closed and click on the desktop to launch a Finder Window (Command-N). With this window in column view follow the path User>Home folder (it’s the folder with an icon that looks like a house—it may have the user’s name rather than “Home”) and click on the Home folder. With the Option Key pressed choose Library from the Finder Go Menu. “Library” will now appear within the Home folder. Within the Library folder find the folder called Preferences and within it find the folder called “Adobe InDesign” and the file called “com.adobe.InDesign.plist” and delete both that folder and that file. When InDesign is next launched it will create new preference files and the program will be restored to its defaults.
The advantage of manually deleting preference files in this manner is that after you’ve reset up the program (make sure that no document window is open) to your liking, you can create copies of your personalized “mint” preference files (make sure that you quit the program before copying them—that finalizes your customization) and use them in the future to replace any corrupt versions you may need to delete.