When using the Ribbon Workbench tool in XrmToolbox, you may run into this error when trying to open it:
An error occurred when trying to display this tool: Unable to cast object of type ‘Microsoft.Xrm.Tooling.Connector.CrmServiceClient’ to type ‘Microsoft.Xrm.Sdk.Client.OrganizationServiceProxy’:
To resolve this, go to Tool Library:
Select the Ribbon Workbench and click Uninstall:
This will restart XrmToolbox. Now, go back to Tool Library and Install the Ribbon Workbench: