Okay, I could fix the issue. The problem was my statement for resetting the plot.
I used the following:

for( int g=0; g<3; g++ ) { ui->plot_acceleration->graph(g)->data().clear(); } ui->plot_acceleration->replot();

Then I tried the following like it is mentioned here:

pq_plot->graph(g)->data().data().clear();

But then the error occurs:

error: member reference type 'QCPDataContainer<QCPGraphData> *' is a pointer; did you mean to use '->'?

Then I used the autocorrection of Qt creator ('->' instead of ' . ')

for( int g=0; g<3; g++ ) { ui->plot_acceleration->graph(g)->data().data()->clear(); } ui->plot_acceleration->replot();

And it is working now. Still don't know what exactly happens with the plot, when I use the first statement... When I use the first statement the plots are also gone after clicking on reset...

Hi,

seems that for some reason on your Windows machine QPrinter is very slow.
I suggest to open a BUGREPORT; provide as many information as you can