FSRef runtime error (Xojo Framework)

A customer gets the below error when using my app. I cannot reproduce this on my systems though.
The customer is running macOS10.14.4

FSRes is deprecated but it is included in the Xojo Framework.
Any pointers to look for? Why is it still used in the Xojo Framework?

I saw this error today running on 10.13.x it was related to getfolderitem("") I think. App is code signed and was built on that machine, restarting the app made the problem disappear.

Might be a “bad” file name. Could it be that you have a NUL char or a “:” in the file name? That’s the only two that are not permitted on a Mac.

Mind you - if you’re using FolderItem, the class “HFS path” naming rules are used, where “:” is used for the path delimiter. That’s the same that the Finder still uses. Meaning, in Xojo’s FolderItem and in the Finder you can name a file “a/a” but not “a:a”. The “:” then gets swapped with “/” if you’re using POSIX or Shell paths.

Meaning, if the Finder shows “a/a”, the file’s name in Terminal will be “a:a”.