Trying to run an Excel 2013 VSTO Add-ins project, and I keep on getting an error that says that:
"System.Security.SecurityException: The solution cannot be installed because it is signed by a publisher whom you have not yet chosen to trust. If you trust the publisher, add the certificate to the Trusted Publisher list."
Try the solutions from the postings here.
As for myself, I've developed an Excel VSTO AddIn with a self-signed untrusted certificate that is delivered by a custom Setup.exe which is then installed on machines that belong to some end-users. I have no control over these machines because the end-users just download my Setup.exe from a public website. After setup the path of the .vsto is a local file path so I don't need a web server as a host.
In my case the following code (placed in my Setup.exe) is enough to successfully trust the Excel VSTO:
UserInclusionList.Add(new AddInSecurityEntry(new Uri(vstoFilePath), "<RSAKeyValue><Modulus>...</Modulus><Exponent>...</Exponent></RSAKeyValue>"));
<RSAKeyValue> can be found in your .vsto file.