.NET CryptographicException “Keyset does not exist”
Came across this error today when updating a new certificate used in a WCF service for digital signatures. Turns out the solution, as always, was pretty simple: give correct permissions to the private key file. Open the certificate manager and locate the correct certificate. Right click and navigate to: All Tasks -> Manage Private Keys. Change the file permissions so the IIS user can read. Read more on stackoverflow.com.