A LabVIEW 2026 BLE application that runs in the development environment but fails as an executable points to a deployment-time dependency or runtime-loading problem; rebuilding and adding files to Always Include did not fix this case. The reported application uses the Windows Bluetooth interface through the BLELib .NET library. Treat .NET loading as the leading investigation path, not as a confirmed root cause: the error details and failing dependency must decide the repair.
Stop repeating the fixes that already failed
The VI runs in the development environment, but its executable fails. The same executable also fails on other computers with either the 2025 Q3 or 2026 Runtime Engine. Earlier LabVIEW builds worked. That comparison narrows the problem to how the application is built, packaged, or loaded; it does not prove which dependency is missing or incompatible.
- Rebuilding the executable: Rebuilds do not correct a dependency-loading or runtime compatibility problem by themselves. Rebuilding was tried without success.
- Adding files to Always Include: This option only helps when the needed file is known, deployable, and compatible with the application. Adding files without identifying the load failure did not help here.
- Switching between Runtime Engine versions: Testing both the 2025 Q3 and 2026 Runtime Engines did not restore operation. Do not treat another runtime installation as the fix unless the error identifies a runtime mismatch.
- Downgrading LabVIEW: The application worked in an earlier release, but downgrading was not the desired production path. Preserve a known-working build for comparison while investigating the 2026 build.
Do not copy DLLs at random or change .NET settings based on a guess. A wrong assembly or runtime target can replace a clear load failure with a different failure, and does not establish that the Windows BLE interface can initialize.
Use the failing VI as a clue, not a diagnosis
The temporary %temp% folder may contain an executable-specific _BrokenVILog file after a failed launch. Inspect it to identify which VI or subVI is reported as broken. That is a useful starting point, but a VI listed in the log is not necessarily the underlying cause: an external assembly can fail to load while a calling VI appears in the report.
In the reported case, inspecting the broken-VI log did not reveal a useful cause. If the log names a VI that calls BLELib, trace the failure from that call into the managed assembly and its dependencies. If it lists no broken VI, or lists VIs without a clear dependency error, capture the executable's debugger output rather than repeatedly rebuilding.
Separate the symptom from the likely failure layer
| Observation | What it narrows down | What to check next |
|---|---|---|
| VI runs in LabVIEW development but EXE fails | Development and executable execution differ in packaging or runtime loading. | Capture the executable error and identify the first failing VI or assembly. |
| Earlier LabVIEW build works; 2026 build fails | A release-related build or managed-code loading difference is plausible. | Compare build settings and the managed assembly's runtime requirements. |
| Both 2025 Q3 and 2026 Runtime Engine tests fail on other computers | Changing only the installed Runtime Engine did not solve deployment. | Check the package contents and whether the required runtime or dependency is available on the target computer. |
_BrokenVILog names a VI but gives no actionable cause |
The log identifies a failure location, not necessarily the failing dependency. | Launch with debugging enabled and wait for a debugger attachment. |
| The application calls BLELib | The .NET boundary and BLELib's own dependencies warrant investigation. | Inspect assembly load errors, required DLLs, and the runtime target actually used by the build. |
A proposed explanation is that LabVIEW 2026 changes how the application loads .NET, possibly selecting .NET Core rather than .NET Framework. That was raised as a possibility, not verified for this application. Read the build's actual .NET target and the BLELib dependency requirements before changing configuration; do not assume a particular default or use an unverified INI setting.
Capture the executable failure with the debugger
Build a diagnostic executable with debugging enabled and set the build option to wait for the debugger. Launch that executable; it should pause while it waits for an attachment. Attach the LabVIEW debugger and reproduce the failure so the error can be examined at the point it occurs.
- Open the executable build properties and enable debugging.
- Enable the option to wait for the debugger in the debugging settings.
- Build and launch the executable on the affected machine.
- Attach the debugger, then reproduce the BLE initialization or device-discovery operation.
- Record the first error, the VI where it occurs, and any assembly or dependency name shown. Preserve the complete error details for the repair or support case.
Use the first meaningful load or initialization error. Later errors may only be consequences of the initial assembly failure. If the debugger never reaches the BLE code, investigate startup and application loading before troubleshooting device discovery.
Inspect BLELib and the executable's deployment requirements
BLELib is the leading dependency to inspect because the application uses it for Windows Bluetooth Low Energy operations. Determine what managed assembly the application loads, what runtime that assembly targets, and whether its dependent DLLs are present and loadable on the target computer. The executable's successful build does not by itself prove that every external dependency will be available at runtime.
- Identify the exact BLELib assembly and its dependent assemblies from the project and debugger/load error.
- Check the library's documented .NET target and compare it with the target selected by the LabVIEW 2026 build.
- Check whether each required DLL is included in the deployment or installed by a documented prerequisite. Confirm architecture and version compatibility from the library's own documentation or assembly metadata.
- Compare the 2025 Q3 and 2026 build settings for managed-code configuration and dependency deployment. Change one setting at a time and record the result.
- Only add a dependency to the build after confirming that the application requires that specific file and that redistribution is permitted.
A DLL installed globally on the development computer may not be available on a clean target machine. Conversely, bundling an assembly already provided by a supported runtime can create version conflicts. Verify what the application resolves at launch rather than copying files into arbitrary folders.
Build a controlled test before restoring deployment
Use one clean test machine and one diagnostic build at a time. Keep the project, build settings, executable, Runtime Engine, and dependency package identifiable so the 2025 Q3 and 2026 results can be compared. Because the reported executable failed with both tested Runtime Engines on other computers, testing again should focus on the dependency and runtime target, not simply on installing each runtime repeatedly.
- Retain the last known-working earlier-version build and record its dependency package and build configuration.
- Build the 2026 executable with debugging and wait-for-debugger enabled; capture the first failure.
- Make only the correction indicated by that failure, such as supplying a confirmed missing dependency or aligning a documented runtime target.
- Rebuild and deploy to a test computer with the intended Runtime Engine and documented prerequisites.
- Repeat the same launch and BLE discovery test, then remove diagnostic settings only after the deployment passes.
Do not label a build fixed because it starts. The BLE application must also reach its expected discovery operation on the target computer. Keep the diagnostic build available until that full check passes.
Verify both startup and BLE operation
Verify the same executable on a development computer and a separate target computer. The target should represent the intended runtime-only deployment, not a machine whose development installation may supply dependencies silently. Confirm that startup completes, the debugger no longer reports the original load failure, and the BLE path performs the operation the application is meant to perform.
Compare the deployed dependency set with the set identified during debugging. If startup succeeds but discovery still fails, treat that as a separate Bluetooth or device-discovery problem; do not infer that the packaging repair failed without checking the new error. Record the LabVIEW build version, Runtime Engine version, build options, resolved .NET target, dependency versions, and exact error text for repeatable testing.
FAQ: LabVIEW 2026 BLE executable failures
How do I find which VI breaks in a LabVIEW executable?
After the failed launch, inspect the executable-specific _BrokenVILog file in %temp%. Use it to locate the reported VI, then trace any external library calls because the listed VI may not be the underlying dependency failure.
How do I debug a LabVIEW executable that fails at startup?
Enable debugging in the build properties and select the option to wait for the debugger. Launch the executable, attach the debugger, and capture the first error and the VI or assembly involved.
How do I check whether BLELib is causing the failure?
Use the debugger's first load or initialization error to identify the assembly, then check BLELib's documented .NET target and required DLLs against the 2026 build and target computer. Do not assume a missing DLL until the error or dependency inspection identifies it.
Will adding DLLs to Always Include fix a LabVIEW 2026 BLE EXE?
Only if you have identified a required, compatible, redistributable DLL that the build omits. Adding unspecified files did not fix the reported failure and can introduce version conflicts.
Should I switch back to the 2025 Q3 Runtime Engine?
That test did not restore the executable on other computers; the 2026 Runtime Engine test also failed. Compare build settings and dependency requirements, and use the debugger to determine whether the failure is a runtime mismatch or an assembly-loading problem.
Stop changing runtime settings or copying DLLs when the first load error remains unclear. Escalate to official NI support with the broken-VI log, debugger output, build properties, Runtime Engine versions, and the BLELib dependency details; ask the library maintainer as well if the error identifies BLELib or one of its assemblies.