DavCInt User Agent and Options Verb Requests

We are getting quite a few errors in our logs where the user agent is DavCInt and verb is OPTIONS. Does anyone know who/what might be making this type of request?

We are using ASP.NET MVC and all of our controller actions are decorated with HttpGet or HttpPost as appropri开发者_如何学编程ate so a controller supporting the request is of course not found.

I know I can deny verbs in the web.config but I am looking for any insight before I do so.