Have CanoScan 9000f MK11 connected via USB to an iMac running OS El Capitan 15 11 5. Have been Using Scanner thru the OS but today the scanner disappeared from System preferences and if I try to add it back the OS can't find it. It shows up in the System Report as being connected! I've tried rebooting and reconnecting the USB cable but to no avail. Any ideas would be welcomed. Thanks.
