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                          ERROR - Exception reading manifest from file Exception reading manifest from file:///C/Program%20Files/ANSYS% 20inc/v251/optiSLang/lib/optiSLangExcelAddln.vsto:

                          Authored by Caleb Scharf March 10th, 2025 914 views 10 likes KB3087544

                          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.
                            • You may need to open excel as an Administrator by Right clicking and selecting Run as Administrator. 

                               

                           

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