Thank you for your message.
Could you please clarify if you are able to try installing the Viewer to another machine and see if the issue occurs there as well? This would help to isolate the issue first, as it might be caused by external factors that might be specific to a certain machine, such as antivirus software activity.
If the issue only occurs on this specific Viewer PC, please check your antivirus software settings, and specifically add both Viewer and Host to its exceptions list (white list).
Also, please try resetting the Viewer configuration file that perhaps was somehow corrupted by antivirus software.
Please, try the following:
1. Fully exit the Viewer File -> Exit.
2. Locate the file config_4.xml in the C:\Users\[Your_username]\AppData\Roaming\Remote Utilities Files\ folder.
Please note that the AppData folder might be hidden by default in which case you need to enable "Hidden files and folders" in Windows Explorer settings.
3. Remove the config_4.xml file from that folder.
This will reset the Viewer settings. Your address books won't be affected by this action. However, you might need to register the Viewer with your license key again.
4. Run the Viewer and see the issue still persists.
Hope that helps.