This is a known issue that has to do with the latest insider preview of Windows (Microsoft Windows NT 6.2.9200.0 (Microsoft Windows 10 Pro Insider Preview). Unfortunately, Microsoft seems to have messed up the RDP ActiveX control in the latest build that causes a crash when opening more than one RDP session simultaneously. 

Until Microsoft releases a fix for this issue, there are two possible solutions for this problem:

1.)Rollback to a stable version of Windows.

2.)Some of our users have reported that replacing the .dll with a .dll from another version of Windows 10 pro fixes the issue. Disclaimer: We have not tested this and replacing .dll is not officially supported by Microsoft or advised by us!

Please Note:  We know that many of our users are IT professionals and in general early adopters with access to Windows Insider builds. We strongly recommend against using Windows Insider builds due to their inherent instability and unforeseeable bugs like this one. If the machine running Royal TS is used for critical/production work, please use a stable version of Microsoft Windows.

Call to Action - If you are experiencing this crash, make sure you use the Feedback Hub application to submit a bug report to Microsoft!