Related to QTBUG-47379.
QSettings only works with Alternate Data Streams (ADS) if the path includes two periods. For example, when writing data to "c:\test.txt:ea.ini" the calls to QSettings::setValue(..) will not indicate a failure, but the data will not be written to the QSettings file. However, if the path is "C:\test.txt.ea:ea.ini" (with a meaningless initial ".ea") the settings are written correctly to the file.