I have an iMac under OS X Yosemite 10.10.5 and an external hard drive with 3 partitions.
The external hard drive was unplugged and left unplugged. Since then, it appears on my desktop at each startup, in black and white. It can be ejected at any time (with orderE or Disk Utility), but always returns at each startup.
If I plug the hard drive, it also appears in color in addition to fake HD icons in black and white. It can be ejected and comes back only if I reconnect it. By clicking on the false icon, the right menu is displayed. All documents and applications are also accessible.
How to get rid of B & W icons?