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Manifest XML signature is not valid.

Manifest XML signature is not valid.

Owned by Andreas Schmidt
Last updated: Jan 18, 2019 by Tobias Viehweger

Problem

During start of the addin, you get the following error:

System.Deployment.Application.InvalidDeploymentException: Exception reading manifest from file://MyPath/MyAddIn.vsto:
the manifest may not be valid or the file could not be opened.
---> System.Deployment.Application.InvalidDeploymentException: Manifest XML signature is not valid.
---> System.Security.Cryptography.CryptographicException: SignatureDescription could not be created for the signature algorithm supplied.

Solution

You are using either an outdatet .NET or VSTO Runtime. Please download and install the latest runtimes:

Update VSTO Runtime  (Requires 10.0.40820)

https://www.microsoft.com/en-us/download/details.aspx?id=54251

Update .NET Runtime (Requires 4.6.2)

https://www.microsoft.com/net/download/dotnet-framework-runtime