Hi Mathias! My name is ***** ***** it is my pleasure to assist you today.
Let's try this: navigate into your Applications folder via Finder, and open Utilities. From there, open Activity Monitor. Once there, look for anything anything matching SafariCloudHistory*, select each, and then force-quit those processes (using the octagonal-shaped button in the upper-left corner of the window).
I think that will do it! Please let me know if you need any additional assistance.
Hi Mathias: I'm just checking back with you to see if my previous suggestion -- removing instances of SafariCloudHistory from Activity Monitor -- helped insofar as enabling you to install InDesign? If you're still having trouble or would like additional assistance, please let know.