Without warning, the thumbnails of my recent files (lots of them) have vanished when InDesign opens. I can find them in the dropdown list of Recent Files, but it's obviously easier to pick them from thumbnails. As it is right now, the space where they appeared is now completely blank. Help? Working on a PC Windows 10.
Try resetting your preferences: The easiest way to reset everything is to delete the InDesign preferences: as soon as InDesign starts to boot hold down Shift, Alt, Ctrl (and Apple/Cmd if working on a Macintosh). A dialog will appear asking to delete the InDesign Preferences, select 'Yes' on this dialog. Further info and instructions here if needed: https://helpx.adobe.com/in/indesign/kb/indesign-preferences-support-file-locations.html