Dynamics365 PluginRegistration tool throws Error - Assembly must be fully signed (not delay signed) though you are uploading signed dll.

You might be here because you are getting this misleading error "Assembly must be fully signed (not delay signed)" although you have successfully generated signed dll either locally or from VSO server. I am documenting this specific error scenario here as I couldn't find anything available over the internet.

I had generated fully signed dll using our VSO build definition. When I am uploading this dll to PluginRegistration tool using the assembly “Update” option, it kept throwing the below exception:

Unhandled Exception: System.ServiceModel.FaultException`1[[<>]]: Action failed for assembly << TRIMMED >>: Assembly must be fully signed (not delay signed).

Detail: …

Earlier we were able to update the build generated assembly right from this tool.

We are using the task "ESRP CodeSigning" for code signing process. When I checked the history of this definition someone had modified it’s configuration.

So during update process it’s failing to match with existing assembly key. Hence, it fails out with this misleading error message during update process.

Don’t worry solution is pretty simple

as mentioned in below steps:

Remove the existing assembly by using unregister command.
Select “Register New assembly”
Choose the dll you need to register >> Select the plugin and workflow activities
Hit “Register Selected Plugins”

That’s it. It should be good now.

Have a great time!

Originally posted on Things on Tech.