Does not works on 10.13.6 means nothing, I know, but this is what I get on both the generated (on El Capitan) application and the project run on the IDE (2015r1).
In fact, at application run time, a check is done for the presence of a target folder (where data will be downloaded), then (at PushButton.Action) another folder (inside the previous one) and, depending on its presence or not (and a user selection), the second one is created.
That folder is not created, and no download item(s).
I waited for some times (some minutes: the compiled application, then one minute, still "running") and that specific folder was not even created.
The “Download folders" does resides in the macOS download folder, the compiled application in the project folder (so not in the Applications folder).
Is there’s something wrong above ?
Same behavior with Xojo current version, project run in the IDE.
10.13.6 behavior ? (I do not had any warning)
Clues are welcome. TIA