Error 1124 When Adding Custom Device to VeriStand

Issue Details

When I try to add my custom device to VeriStand I get error 1124 - VI is not executable or VI is not loadable.

Error 1124 occurred at Open VI Reference in sub_Launch Control.vi->Workspace.vi

In a built application, this error might occur because the VI being loaded was last compiled for a different OS or with CPU features, such as SSE, that this target does not support. In this case you must rebuild the application for the target OS and make sure SSE compiler settings in the build specifications match the target platform. This error also might occur if the VI is a polymorphic VI, which cannot be loaded in the LabVIEW Run-Time Engine. You must load an instance of the polymorphic VI instead of the polymorphic VI itself.

or

Error 1124 occurred at Open VI Reference in Custom Devices Storage.lvlib:Initialize New Custom Device.vi

Possible reason(s):

LabVIEW: (Hex 0x464) VI is not loadable.

Solution

This error occurs because the custom device has been compiled in the wrong bitness for your version of VeriStand.

VeriStand 2020 R6 and previous use a 32-bit engine and therefore requires any custom devices to be created/compiled in LabVIEW 32-bit. 
VeriStand 2021 and later use a 64-bit engine and therefore requires any custom device to be created/compiled in LabVIEW 64-bit.
 

VeriStand 2021 and Later

This error occurs if you have built the custom device using a 32-bit LabVIEW.
Open the source code (preferable on the PC where VeriStand will be running, but a computer of the same OS and bitness will usually be okay) in 64-bit LabVIEW and rebuild  the custom device from 64-bit LabVIEW. 

If VeriStand is open, you must close and reopen it for any changes to the custom devices folder to be updated. Now you can add the custom device to the VeriStand project. 

When moving from a 32-bit to a 64-bit version of VeriStand for the first time, if there is not already a Linux PXI target added to the project then there will be some edits you need to make to the custom device in order to build it successfully.
Follow the steps in Creating a LabVIEW 2021 64-Bit VeriStand Custom Device LabVIEW Project to edit the XML of your existing custom device LabVIEW source project, allowing you to now build 
 

VeriStand 2020 R6 and Previous

This error occurs if you have built the custom device using 64-bit LabVIEW.
Open the source code (preferable on the PC where VeriStand will be running, but a computer of the same OS and bitness will usually be okay) in 32-bit LabVIEW and rebuild the custom device from 32-bit LabVIEW. 

If VeriStand is open, you must close and reopen it for any changes to the custom devices folder to be updated. Now you can add the custom device to the VeriStand project. 

Additional Information

Note, VeriStand 2021 and later drop support for Phar Lap and Linux ARM targets. Linux x64 targets are still supported.