Time Machine does not recognize external drive at start up
I have an external WD 2TB drive which I use as my Time Machine back up drive. When I restart the iMac desktop the Time Machine drive does not start automatically and I must open Time Machine each time and remember to identify the external drive that contains my Time Machine back up data. Is there some way to make this drive the default Time Machine back up device when the system starts? It is annoying to have to remember to do this each time my machine restarts. I have a drive icon that displays as "My Book" on restart where the Time Machine icon is located but this icon is yellow and my Time Machine drive icon is blueish green. Once I set the correct drive it will go into the mode to refresh the backup (usually in 118 seconds) and then once the backup is updated then the icon become blueish green and all works normally. Please help! Thx Tom