I am having a similar problem. I have an iOS app which works fine. When I run on my Mac (built for iPad, not Mac Catalyst) it crashes when trying to save to a file. It is crashing in the call SHKSaveToFilesSharingService->[NSSavePanel setNameFieldStringValue:] I have attempted the share using simple text rather than a file and the results are the same. So the problem doesn't appear to be with saving a file, but rather with saving TO a file. This suggests that it is not a sandbox access problem. Other share options work correctly, both with a file and a string.