ERROR

Every time excel is opened the follow error occurs. 

Installing Office customization

There was an error during installation.
Name:

From: file:///C:/Program Files/ANSYS
lnc/v251/optiSLang/lib/optiSLangExcelAddln.vsto

Exception reading manifest from file:///C/Program%20Files/ANSYS%
20inc/v251/optiSLang/lib/optiSLangExcelAddln.vsto: the manifest may not be valid
or the file could not be opened.


Name:
From: file:///C:/Program Files/ANSYS lnc/v251/optiSLang/lib/optiSLangExcelAddln.vsto
************** Exception Text **************
System.Deployment.Application.InvalidDeploymentException: Exception reading manifest from file:///C:/Program%20Files/ANSYS%
20inc/v251/optiSLang/lib/optiSLangExcelAddln.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: The form specified for the subject is not one supported or known by the specified trust provider.
at
System.Deployment.lnternal.CodeSigning.SignedCmiManifest.Verify(CmiManifestVerify
Flags verifyFlags)
at
System.Deployment.Application.Manifest.AssemblyManifest.ValidateSignature(Stream s)
--- End of inner exception stack trace ---

Software & Version

***OptiSLang 2025R1***

*This example was taken from this version but is not necessarily limited to this version.

Description/Cause

This occurred after installing Optislang 2025. 

This is because the optiSLang excel add in is not available in 2025.  Its a known issue and will likely be fixed in a service pack. 

Solution

1. Open Excel > File > Options > follow the picture below.