Error 102 Error registering plugins and/or workflows. Plug-in assembly does not contain the required types or assembly content cannot be updated. C:\Program Files (x86)\MSBuild\Microsoft\CRM\Microsoft.CrmDeveloperTools.12.targets
This error usually occours whenever you tr y to deploye and register a plugin via Visual Studio CRM Deployment. If you have deployed same plugin or workflow in the past but now something has changed but CRM steps/process is still expecting same steps but in your new code don’t exist then it will throw error.
Only solution to this to deactivate and delete any steps/process assoicated to this assembly and then delete the assembly itself in solution as well.
Once done you will be able to deploy Plugin/Workflow with out any errors.