15640 is an app package result. The local Windows en-US message table describes this value as: “An optional package with a FullTrust entry point requires the main package to have the runFullTrust capability.”
Code reference and safe checks
Read the exact screen and operation before selecting a repair. This page does not run commands or collect files, keys or logs.
What this value means
The local Windows en-US message table describes this value as: “An optional package with a FullTrust entry point requires the main package to have the runFullTrust capability.”
ERROR_INSTALL_OPTIONAL_PACKAGE_REQUIRES_MAIN_PACKAGE_FULLTRUST_CAPABILITY is a Win32 system result, usually returned to an application or API caller. It is not a Windows blue-screen code or a diagnosis of the whole PC.
| Code | 15640 |
|---|---|
| Hex form | 0x3D18 |
| Symbol | ERROR_INSTALL_OPTIONAL_PACKAGE_REQUIRES_MAIN_PACKAGE_FULLTRUST_CAPABILITY |
| Windows family | Win32 system codes |
| Source level | Windows en-US message resource |
Safe next steps
- For 15640 (ERROR_INSTALL_OPTIONAL_PACKAGE_REQUIRES_MAIN_PACKAGE_FULLTRUST_CAPABILITY), record the package name, installed version, Windows build, and whether this is install, update, move, or removal.
- Check the app publisher’s official package and Windows AppXDeployment-Server events for the specific operation.
- Back up app data before uninstalling or resetting a package; on managed PCs, check policy with IT.
After one step, repeat the original operation and record whether this same code returns. A different code needs a fresh interpretation.
What this code cannot prove
This wording came from the local Windows en-US system message table. The symbolic name is from the source dataset’s historical Boost mapping; a matching current Microsoft web pair was not found in the checked lists. Verify the exact number and applicability on the affected device.
If the result differs from the documented message or a repair could remove data, stop and use the official source or vendor support.
Official reference and verification
Source type: Windows en-US message resource. Checked against the source set on Nov 2, 2026.
The reference gives the meaning of this identifier. It does not inspect your PC or guarantee that one repair will work.