Don have you checked my post from 24-10-18? That didn't fix it for you? You could always rename the XML completely, and then RU will create a new blank one. Then create 10 new connections from scratch without putting details in. If you can do this then the XML file is at fault. Otherwise you can delete the new one and reinstate the old XML file without losing any saved details.
However going through the XML and fixing it worked for me originally. I've had the problem since but fixed it each time by deleting out the 'ghosts' in the XML.
Found the answer! In %appdata%\Roaming\Remote Utilities Files is an XML called "connections.xml" or similar, and in this is a complete list of all connections in XML format. There were several entries that weren't showing up in RUT viewer, I deleted these and all is good again!
I can't connect to any of my connections because apparently "My license does not allow using this key for more than 10 computers" - yet I only have 8 connections. How can I get this working? I had 10, yesterday added a new one and got the message, then I removed 3 old unused connections but still getting this error.