Hi,

I believe there is an event to start the workflow when the item is checked out. Perhaps, you could set up something similar to this.

1. Start when an item is checked out.

2. Get Document Reference Step for the document in the library.

3. Set Data field step to capture the user information (email) using the reference from step (2).

4. Use the Check Out User data field in the To field of the email step to send out the email to that user.

Thanks!

My document library doesn't have "Check out" required. Is there any other way we can find users having access to a document?

Thanks