The Indesign CS6 on my Mac can't be used, not long ago, it was even uninstalled automatically.
What is the reason? And how can I deal with it?
If you have Mac El Capitan or later operating system your CS6 is not compatible due to Apple not maintaining compatibility with older programs
READ HERE https://forums.adobe.com/thread/2301916 for information, including a link to installing the old Java runtime that is required
InDesign has not been known to uninstall automatically, this may be a new issue. There will be no fix so reinstall.