Hi, I want to create: Group "0", "Channel1", "Channel2", "Channel3"...; Group "10", "Channel1", "Channel2", "Channel3"...; Group "20", "Channel1", "Channel2", "Channel3".... for a TDMS file. When I use the attached VIs, it did not work properly. I do not know why? Any help will be appreciated. Thanks, Steve

@Shijie wrote: Do you have any idea how to get around it for my application for the time being? Yeah attached is an updated Save sub that should work I just tested it quickly. It doesn't ask for just one group's channels, but all. Then we iterate over all group channel pairs, looking for the right group, and the channels to have "Channel" in them. @Shijie wrote: By the way, have you reported the bug to National Instrument yet? That's what these forums are for, I suspect there is an NI engineer trying to isolate the issue as we speak (or soon) they usually reply after getting a concrete answer on "This is a bug" or "No you dummy you did it wrong". I'm pretty confident this is a bug, especially since it gets different results from 2014 or 2015.