Error -1074134966 When Attempting to Load Custom Bitfile on the PXIe-5646R

Issue Details

I recently upgraded the NI-RFSA, NI-RFSG, and RFmx software from versions 2025 Q2 (or older) to the 2026 Q2 versions. After upgrading the software, I am now getting the following error when attempting to load a custom bitfile to my PXIe-564x VST device:

    Error -1074134966 occurred at niRFSA Initialize With Options.vi

    Possible reason(s):

    IVI (Hex 0xBFFA004A) The option string parameter contains an entry without a value (nothing after the '=').

The error is shown in the following dialog box.

Why am I now getting this error and how can I resolve it?

Solution

If you are using the first generation of Vector Signal Transceivers (PXIe-564x), this error is a reported bug found in the software versions between 2025 Q3 and 2026 Q2. This error has since been resolved in the 2026 Q3 software versions. 

Please upgrade to NI-RFSA, NI-RFSG, and/or RFmx 2026 Q3 to resolve this issue. 

You can find more information for using the NI-RFSA or RFmx Initialize function option string input parameter for loading a custom bitfile in this knowledge article. 

If you are still experiencing this error after upgrading to the 2026 Q3 or newer software versions, please contact NI Technical Support.