@M4chin3,

I reimplemented it with readyRead() usage and it seems to work.
Hmm.. It is very interest and strange.. Can you please also, in additional, provide a your project's source code?

@ChrisW67,

if to be honest, in Windows use of a additional thread is desirable, because still there is this bug with a freezing: https://bugreports.qt-project.org/browse/QTBUG-34946