NOTE: IF you are noticing this error as a direct result of installing WebDrive 1.1.15, there was an issue with the installer where a particular necessary file was not always installed. Please install Version 1.1.16 (now available on the WebDrive.com website, as well as through Check for Update within the WebDrive app). This will resolve the issue.
As the error suggests, try restarting the computer if you have not yet already.
If the issue remains and you are not on the latest version, please update to the latest available version of WebDrive and then restart the computer.
If the issue remains, ensure all sites are disconnected in WebDrive, and then reinstall the existing version of WebDrive, and then try again.
If
the connection still won't succeed and you are seeing the same error,
it may be due to a drive letter already being used or not available. Go
into the main app Settings and enable the option for "Automatically
select drive to use" and then try the connection again. This setting will have WebDrive first attempt the assigned drive letter you've chosen for the connection, and if it fails for any reason, WebDrive will instead use the first available drive letter on your system.