PXI Slot Detection Broken After WLAN Toolkit Upgrade

Updated May 10, 2019

Reported In


  • Measurement and Automation Explorer (MAX)
  • WLAN Measurement Bundle


  • PXI Platform Services

Issue Details

On a machine that has NI PXI Platform Services, NI-VISA Runtime, or NI-XNET Runtime installed, one of the following issues can be caused by the WLAN Toolkit installer:
  • niqpxi.dll is downgraded when you upgrade the WLAN Toolkit
  • niqpxi.dll is removed when you uninstall the WLAN Toolkit
This might cause:
  • PXI devices to disappear from the device tree in NI-MAX
  • Incorrect detection of a PXI slot.
The most obvious indication of this error is that the PXI slot of a device is reported as -1 in NI-MAX or when you query this information via the NI system configuration API. The presence of the niqpxi dll can be verified at the installation location at C:\Windows\System32.
The downgraded version of the niqpxi dll will have the version (1.0.0f0).


The solution to this problem is to execute a repair for one of the following installed software distributions:

  • NI PXI Platform Services Runtime version 15.0 or later

  • NI-VISA Runtime version 15.0 or later

  • NI-XNET Runtime version 15.0 or later

To execute a repair on any one of the aforementioned software, complete the following steps:

For Windows 7:

  1. Launch the Control Panel by selecting Start» Control Panel.

  2. Double-click Programs and Features

  3. Select National Instruments Software.

  4. Click the Uninstall/Change button.

  5. Select the software to be repaired from the dialog box that appears.

  6. Click Repair.

For Windows 10/8.1:

  1. Right-click on the Start button.

  2. Select Control Panel.

  3. Select Programs» Programs and Features.

  4. Select National Instruments Software.

  5. Click the Uninstall button.

  6. Select the software to be repaired from the dialog box that appears.

  7. Click Repair.