If your are using Swift, then you must also include module name when you specify the principal class in the info.plist like this: <key>NSExtensionPrincipalClass</key> <string>$(PRODUCT_MODULE_NAME).FileProvider</string> I also did what you described above and it works for me: https://developer.apple.com/forums/thread/122351?answerId=645095022#645095022

Hello, this is how I got it to launch: https://developer.apple.com/forums/thread/122351?answerId=645095022#645095022

Hi @nslx, You have to add a file provider domain from your app using the NSFileProviderManager class. See the example in my previous comment, I believe it has all the details: https://developer.apple.com/forums/thread/122351?answerId=645095022#645095022 Also be sure to keep the Console.app open as it can be very informative with errors.