Application builder error 1003: "..an internal compiler failure "

[Mads]

When building applications in LabVIEW I seem to struggle more and more since upgrading to LabVIEW 2025 Q3 (from 2022/2020) with object cache issues (bad VI when builing).

Typically this error:

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Error 1003 occurred at AB_Targetfile.lvclass:Validate_PostProcessing.vi -> AB_Build.lvclass:Copy_Files_Core.vi

Possible reason(s):

LabVIEW: (Hex 0x3EB) The VI is not executable. This error may occur because the VI is either broken or contains a subVI that LabVIEW cannot locate. Select File>>Open to open the VI and verify that you can run it.

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The build log gives this entry:

[ERROR]

Code:1003

The following VIs could not be built due to an internal compiler failure caused by a defect in the build system. Contact NI Support and include the details below.

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The "Bad" VI in question is always executable if you open it because then it will find its dependencies on the fly anyway, but to get the build working again I have to force a recompile first.

This will give one build with no errors, but if the build is then restarted it will fail the second time even though nothing else was done in-between. 

If all callers are opened and force-recompiled before the build, the build works fine again - once.

(Note that the build does *not* disconnect type defintions, nor does it remove unused polymorphic functions…as recommended for error 1003.All alternatives have been tested too though.)

The way I «fixed» it was to create a new build spec. So why did that work? Well, I suspected (and have confirmed) that it was because the original one had a lot of Custom VI Properties in Source File Settings that disabled debugging. This had not been put back in.

If a lot of Vis share dependencies e.g. and some have debugging enabled others not….Perhaps that messes up the build process /cache, and there is a bug that gets triggered when the build process has run once, causing the Vis to be «Bad» on the next build? I know enabling debugging is one of the  recommended options when running into build issues so there is obviously some problem there, but it is not exactly right to include debugging options in a final build…

PS. As an experiment I have also tried to use the fast file format option. This result sin LabVIEW crashing during the build...

[Mads]

One additional note is that clearing the object cache before rebuilding the application does not seem to be sufficient, only a forced recompile.

I also checked with an AI what it could tell about the issue and it seems to confirm my suspicions but have more insight than I could gather by browsing the usual forums myself, especially the section highlighted in red below:

Why This Happens

1. Debugging Disabled in Build Specification:
   • When you disable debugging in the build specification (e.g., by checking "Remove block diagram" or "Disable debugging" in the Advanced settings), LabVIEW strips out the block diagram and debugging metadata from the VIs during the build process. This results in a leaner executable but modifies the compiled object cache for those VIs.
   • LabVIEW’s compiled object cache stores precompiled code to speed up subsequent builds or execution. When debugging is disabled, the cached compiled code may become incompatible with the development environment's expectations, especially if the VIs are still open in memory or if the cache isn’t properly cleared.
2. Cache Inconsistency After Build:
   • After a successful build with debugging disabled, the compiled object cache for the VIs may be altered (e.g., block diagrams removed or metadata stripped). If you attempt to rebuild without forcing a recompile, LabVIEW may try to reuse the cached compiled code, which is now in an inconsistent state (e.g., missing debugging information or block diagram data that the development environment expects).
   • This mismatch can cause the build to fail with errors related to VI compilation, missing block diagrams, or corrupted VIs.
3. Force-Recompile Requirement:
   • Forcing a recompile (e.g., by pressing Ctrl+Shift+Run in the development environment or manually clearing the compiled object cache) regenerates the compiled code for all VIs, restoring the cache to a consistent state that includes debugging information (if enabled in the development environment). This allows the next build to succeed, but the cycle may repeat if debugging is disabled again in the build specification.

Root Cause

This behavior is often tied to:

• LabVIEW’s Compiled Object Cache: The cache stores compiled VI code to optimize performance, but disabling debugging modifies this cache in a way that can confuse subsequent builds.
• Version-Specific Bugs: Certain versions of LabVIEW (e.g., LabVIEW 2013, 2015, or earlier) have known issues with cache management when debugging is disabled, leading to build failures. These issues may persist in later versions depending on the specific configuration.
• VI State in Memory: If VIs are open in the development environment during a build with debugging disabled, LabVIEW may not properly update the in-memory state, leading to inconsistencies.

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As this seems to be the case with 2025Q3 as well, is there a plan to redesign this bad partnership between object caching and application builds? I will try to programatically clear the cache before builds, as I see some automation tools out there already do, but since the manual clearing is not always sufficient that might not be enough...and I expect it will slow down the build process too.

[Mads · Accepted solution]

Well, adding a clear compiled cache to the Pre-Build Action.vi works...It is just a workaround, but at least then we can still disable debugging and get the builds done: