Experiment won't close due to NI-DAQ device

Hi Sujay,

Recapping the problem you’ve been having and what we’ve learned about it so far:

  • You upgraded to a recent nightly build. (It includes the new app icons, so you must have downloaded it on or after March 1.) Since upgrading, you’ve found that MWorks experiments won’t close, and you have to force quit and restart MWClient and MWServer.

  • After some investigation, we discovered that the problem was caused by MWNIDAQPluginHelper, a helper process used by MWorks’ NI-DAQ interface, failing to close. When we opened Activity Monitor and force quit the helper process, the hang was resolved, and experiment closing completed as usual.

  • In your setup, you use a PCIe NI-DAQ device. I have attempted to reproduce the problem on my Mac Pro using a USB NI-DAQ device, but so far I have been unable to do so.

  • I suggested that you upgrade to the latest NI-DAQmx Base. You tried this, but it didn’t resolve the problem.

Does that all sound correct?

If yes, then I have some additional questions:

  1. What version of MWorks were you using before you started having this problem?

    Not long ago, you had upgraded to an earlier nightly build in order to take advantage of the new MWK2 data file format. Were you still running this earlier nightly build on your setup before you upgraded to the more recent nightly (the one with the new icons)? Or had you reverted to MWorks 0.8 or some other version?

  2. Have you made any other changes to your setup recently? In particular, have you added new hardware or installed any other new software?


Hi Chris,

That sounds right.

I was using 0.9.dev-20180801 version. I did the upgrade on March 12th.

Besides upgrading mworks, no changes have been made. I upgraded it because
the file size was smaller in the new verison.

Hi Sujay,

Thanks for the additional info.

I have made some changes to the NIDAQ interface since the 20180801 nightly you were using, so it seems likely that one of those changes lead to the issue you’re seeing now. Unfortunately, the changes included some necessary fixes to address other issues that had come up, so I can’t just revert them.

Is there some time I can stop by to run some additional tests on your setup?


Hi Sujay,

The fix for this issue will be in tonight’s nightly build.