I'm working on a task and wanted to find a certificate from the Local Computer store based on its Thumbprint and ran into the below exception. If you are trying something similar you might get the below exception if you COPY the value from the Certificate MMC snap in. System.FormatException: Invalid hexadecimal string format. at System.IdentityModel.SecurityUtils.DecodeHexString(String hexString) at System.IdentityModel.Selectors.X509CertificateStore.Find(X509FindType f...