dotnet/wpf · error · FileFormatException

SR.PackageSignatureCorruption

Error message

SR.PackageSignatureCorruption

What it means

DeleteRelationshipToSignature removes origin-part relationships pointing at a signature being deleted; if such a relationship has an external target instead of an internal signature part, it throws FileFormatException (SR.PackageSignatureCorruption), signaling corrupted signature structures in the package.

Solutions

1. Catch FileFormatException around the removal API and mark the package's signature block as unusable.
2. Re-create/re-save the package with a conformant producer to rebuild internal signature relationships.
3. When writing signature infrastructure, always add signature relationships with TargetMode.Internal.

Example fix

// before
mgr.RemoveSignature(sigUri); // FileFormatException on external relationship
// after
try { mgr.RemoveSignature(sigUri); }
catch (FileFormatException ex)
{
    log.Error("Signature relationships corrupted; cannot remove signature", ex);
}

foreach (var r in originPart.GetRelationships())
    if (r.TargetMode == TargetMode.External)
        throw new InvalidOperationException("Origin part contains external signature relationships; package corrupt.");

try { mgr.RemoveSignature(sigUri); }
catch (FileFormatException) { /* signature relationship corrupted — rebuild package */ }

When it happens

Trigger: RemoveSignature/RemoveAllSignatures traversal encountering a signature relationship in the origin part whose TargetMode is External rather than Internal — the signature part cannot be resolved.

Common situations: Signature origin parts edited by hand or by non-conformant tools, packages damaged in transit, or relationships retargeted to external URIs by post-processing.

Understand the failure class

Background: Schema validation failed / invalid input schema: payload rejected because its shape doesn't match the expected schema — this error's family across 28 libraries.

Related errors

• Signature structures are corrupted in this package.
• Signature structures are corrupted in this package.
• ' ' ID is not a valid XSD ID.
• Cannot remove signature from read-only file.
• Document contains multiple Rights Management Encryption…

AI-assisted analysis of dotnet/wpf@81131a70a4 (2026-09-14). Data as JSON: /api/errors/4c46c0f33df656e5. Report an issue: GitHub.

Appendix: source

Thrown at src/Microsoft.DotNet.Wpf/src/WindowsBase/System/IO/Packaging/PackageDigitalSignatureManager.cs:1136

                _container.DeleteRelationship(r.Id);

            return true;
        }

        /// <summary>
        /// Deletes any relationship to the given signature from the signature origin
        /// </summary>
        /// <param name="r">relationship from origin</param>
        /// <param name="signatureUri">signatureUri</param>
        /// <returns>true</returns>
        private bool DeleteRelationshipToSignature(PackageRelationship r, Object signatureUri)
        {
            Uri uri = signatureUri as Uri;
            Debug.Assert(uri != null, "Improper use of delegate - context must be Uri");

            // don't resolve if external
            if (r.TargetMode != TargetMode.Internal)
                throw new FileFormatException(SR.PackageSignatureCorruption);

            if (PackUriHelper.ComparePartUri(PackUriHelper.ResolvePartUri(r.SourceUri, r.TargetUri), uri) == 0)
            {
                OriginPart.DeleteRelationship(r.Id);    // don't break early in case there are redundant relationships
            }

            return true;
        }

        private void DeleteOriginPart()
        {
            try
            {
                // remove all relationships of the type "package-to-signature-origin"
                SafeVisitRelationships(_container.GetRelationshipsByType(_originRelationshipType), 
                    DeleteRelationshipOfTypePackageToOriginVisitor);

                _container.DeletePart(_originPartName);

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