NI-RFmx Requires All the Installed RFmx Drivers to Have the Same Version

Updated Aug 9, 2018

Reported In


  • NI-RFmx SpecAn
  • NI-RFmx Demod

Issue Details

NI-RFmx requires that all RFmx drivers and shared components be of the same version on a particular machine for the drivers to work correctly. In some cases, NI installers are not able to prevent a mismatch of versions. When you install an upgrade to a specific RFmx driver, the installer does not know whether you are going to install the upgrades for all the other RFmx drivers you have on your system. A particular case where this situation might occur is if you install the NI RF Device Drivers with NI-RFmx, which includes NI-RFmx SpecAn and NI-RFmx Demod but not the other NI-RFmx drivers.


Before you install or upgrade an NI-RFmx driver, ensure that you are willing and able to upgrade all your other NI-RFmx drivers to the same version. For example, if you already have installed RFmx SpecAn 1.2 and Demod 1.2 on your system, and you want to install SpecAn 2.0, you must also install Demod 2.0 at the same time or in a separate step. If you only upgrade SpecAn to 2.0 version, the Demod 1.2 API will be in non-working state. Refer to Figure 1.

Figure 1. Bad State resulting from partial NI-RFmx upgrade

If you upgrade one or more RFmx drivers, and want to downgrade to an older version, you must uninstall all of the RFmx drivers before reinstalling the older versions. If you do not uninstall all of the RFmx drivers before installing an older version, the newer version of the shared components installed by the newer RFmx driver will remain on the system and will be incompatible with the older versions of the drivers. 

Figure 2. NI-RFmx downgrade process flow 

Additional Information

Note: To check the state of your NI-RFmx system you can use RFmx Compatibility checker (niRFmxCompatibility_Checker.exe). This utility gets installed with any NI-RFmx 2.0 driver and is located at the following locations on disk:

  • 32-bit Systems:  C:\Program Files\National Instruments\RFmx
  • 64-bit Systems: C:\Program Files (x86)\National Instruments\RFmx