Hello, because I spent hours searching for a solution and did not find anyone, and found an error, although I would go and publish it.
I created NSOpenPanel in the same way that everyone creates it, sets the file types that it accepts, and gave it a runModal call, and the program froze for about 15 seconds and then continued to work as if the modal was canceled. The problem was that I used rights with my application, and when in the application sandbox I needed to set access to the user’s file for reading in order for it to work. as soon as I installed this in my project settings, I ran the program again and was able to use NSOpenPanel. good luck everyone.
source share