I am having the same issue. I originally installed a viewer on my PC to try it out, then when I tried to install the viewer on another PC I began to get this message. I was not even sure how the program worked at that point. Once I encountered the error, I then installed the USB key version of the viewer on that type of device. It worked fine in the original network it was installed in. In trying to use it on another network to connect remotely to my original network, I am getting this message. Error: Another user is using this copy of R-viewer. I used the remote utilities program to figure out what level of license to buy. I am the only operator who wants to use the program to connect, at different times between five computers. RU advised me to just get a free license. So, if I am able to use a free license to do this, why do I continue to have this problem. More importantly how do I fix it? Please let me know. Thank you.
Please note that our Free License does not restrict you to a specific workstation - the only limitation for the free license users is that they can only add up to 10 remote connection to their address book. For more information on the Free License please refer to this page.
In this case, if your Viewer is not minimized to the taskbar, then the issue might be occurring due to some files in the Viewer installation folder being somehow corrupted (perhaps, by some firewall/antivirus software activity). Please try the following: 1. Fully uninstall Viewer on the machine where you get the "Error: Another user is using this copy of R-viewer" error message as described in this tutorial and make sure to clean up the previous installation traces. 2. Re-install Viewer. 3. Make sure to add the Viewer's installation folder C:\Program Files (x86)\Remote Utilities - Viewer\* to the exception list as described here. 4. Run Viewer and see if the issue persists.