Most likely, this file would not go missing on its own, so check your Anti-Virus running on your NV Server and make sure that this file has not been quarantined. If it has been removed completely, and nowhere to be found, then take the following steps.
1. Check for a backup of the NV Server to see if this directory and file "nvrascontroller.exe" was backed up. If so, restore the file to the desktop and then copy it into the NVHome/bin directory.
2. If there is no backup of it, on a separate server, install the NV Server, and then go and copy the "nvrascontroller.exe" to the main NV Server. Also, retain the copy of that file, but go ahead and uninstall NV from the second server.
3. If the file is still there and is renamed, check the AV to see if it has been quarantined, if so, you can restore the original back and delete the renamed copy.
Once these steps are validated, you should now be able to see your DR Containers from Device Management as Online.
