it's an odd problem I couldn't unterstand by myself.
I generated some business cards with QR Codes with the DataMerge of InDesign.
The QR Code is genareted by the Windows version perfectly.
But if I generate it with on OSX it's unreadable.
The two platforms generate different QR Codes.
When generating (manually or by DataMerge) a QR Code on one of the platforms, save the document and reopen it on the other platform; then click "edit QR Code …" and just click "OK".
You will see that the QR Code will be generated new and looks different.
Could this be an encoding problem?
sorry this didn't worked.
But good to know how to reset the application preferences (in the future).