## Error message
```text
The app was not detected after installation completed successfully (0x87D1041C).
```

## TL;DR
Intune trusts the detection rule, not the installer exit code. Open the app's detection rules and compare them against what the installer really drops on disk or in the registry, fix the rule to match reality, and redeploy.

## Steps
1. Install the app manually on a test machine and note exactly what files, registry keys, or versions appear.
   Expected: You have the ground truth of what the installer creates.
2. Open the app's detection rules in Intune and compare each rule to that ground truth.
   Expected: You find the rule pointing at a wrong path, version, or key.
3. Correct the detection rule to match the real install output.
   Expected: The rule validates against the test machine.
4. Redeploy the app to the failed devices.
   Expected: Intune reports the app installed.

## When to use
- The exact message appears in Intune app install status
- The installer exits 0 but Intune still reports failure
- The failure started after an app version bump

## When not to use
- The installer itself crashes (fix the installer or its command line)
- The app never downloads (connectivity or cache issue)
- The detection uses a custom script that errors (debug the script)

## Why this happens
Intune declares success only when the detection rule passes after the installer exits. Vendors change install paths between versions, so a rule written for the old version fails on the new one even though the install worked perfectly.

## Edge cases
- 32-bit versus 64-bit registry redirection silently breaks registry detection rules.
- MSI product-code detection is the most robust option when the vendor ships a proper MSI.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_e5CwpRC8Qr5sGB2L_hLHQg