You'd think after Adobe *finally* killed off Flash for good they would remove it from their apps? Apparently not. InDesign refuses to launch for me because it can't find some Flash engine on startup (Startup Scripts CC/Flash/Flash-21.0.jsx). Fix your apps Adobe. Why should we pay a monthly fee for apps that don't work? Just have to convince my boss to switch to Affinity.
Latest version. Checked for updates and there are none. No third party scripts installed at all.
I have no such start up script in my start up scripts folder.
Here's where the folder is on Windows: C:\Program Files\Adobe\Adobe InDesign 2021\Scripts\startup scripts
The folder "/Library/Application Support/Adobe/Startup Scripts CC" (on Mac) is a special script location with entries per application, so they can register themselves as reachable from the other applications via BridgeTalk. E.g. when an InDesign script reveals an image in PhotoShop.
Note (also Bob) that this is a system wide location, not the usual application specific scripts folder.
Apparently removing Flash from your system did not remove the matching folder there, or it was added by some other means. For example, could it be that Apple's migration assistant copied that script folder over from an older machine?
Before you go thru big uninstall/reinstall attempts, just remove that "Flash" folder.