I have an Epson scanner attached to my 64-bit Windows 7 host machine. On that machine it scans fine.
However when I am running a Linux client such as Ubuntu or Fedora, and try to connect to the scanner, I get a message that the host is still using it.
It is showing up properly under the list of USB devices to manage, but the connect option is what is failing.
There are no scanning apps running on the host, and I haven't been able to find a process or service that would appear to be scanner-related.
I have seen some comments about editing some file in a folder under the /etc directory, but I found no such file.