Unable to Create or Open Files on Sonoma 14.6.1 (InDesign 19.5)

[jrg_gcs]

Graphic Design teacher here (high school). One of my 29 students cannot create a new file or open any existing files saved to his InDesign account. All students are working with me step-by-step on the same version of InDesign (no updates) and same iMac computers and for some reason, just one student's is giving him this error message when he clicks "Create" on a new file, or tries to open an existing file:
"No content collected. Collect page item(s) using the Content Collector tool, then place them using the Content Placer tool." 
We've never even touched the Content Collector tools as the students are just learning to use InDesign for the first time together.
Their iMacs are running Sonoma 14.6.1, InDesign Version 19.5 via Creative Cloud for K12 schools.  Thanks!

<Title renamed by MOD>

[Robert at ID-Tasker]

Your screenshot is missing. 

[Mike Witherell]

Here is a thorough troubleshooting guide to work through. Likely a reset for InDesign is needed.

[Bill Silbert]

Try resetting the InDesign preferences on the affected iMac. This process will restore the program to its defaults and, hopefully, fix the issues.

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.