Thank you for your message.
This can be occurring if some Viewer's files were somehow damaged/corrupted (perhaps, by some antivirus software).
Could you please try the following and see if this helps to resolve the issue:
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\
Please note that the AppData folder is hidden by default, so this is why you can't find the Roaming
folder. In this case you need to enable "Hidden files and folders" in Windows Explorer settings. Here's how you can do this
3. Remove the config_4.xml
file from that folder.
This will reset the Viewer settings and remove the current free license key from the key storage as well. Your address books won't be affected.
4. Run Viewer and try registering it with your new license key once again as described here
In case if you have any antivirus/firewall software installed on your Viewer machine, please make sure to add Viewer installation folder to the exception list as described here
- this will help to avoid similar issues in the future.
Hope that helps.