Try to find the reason of the error without a clue from a meaningful error number 
Or read my answer above.
Problem partially solved apparently it is a bug in API 2.0 so far please see Christian’s bug report (https://xojo.com/issue/58856)]https://xojo.com/issue/58856
The feedback link goes to idealab
I fire Feedback directly.
No report found with that number: 58856
[quote=476574:@Emile Schwarz]The feedback link goes to idealab
I fire Feedback directly.
No report found with that number: 58856[/quote]
well I guess it’s something related to their formatting, I guess XOJO could help by providing the correct format for the feedback URL.
Seems one of those “protections against alien files” of Catalina. Files coming from outside, in this case, FAT formatted disks, seems to receive some flag and fails to launch.
Here: <https://xojo.com/issue/58856>