Time Machine icon in menubar is grayed out

The computer i'm using, MBP (about 2012 i think), came with Mountain Lion. I got it in Fall of 2013. I got a Time Capsule for backing up just after i got the computer. In the menu bar on the right side of the upper display, there is an icon for Time Machine. When Time Machine was backing up my computer, several times a day, the TM icon would turn around and around. The icon is a small clock face with an arrow circling it. During back ups, the little arrow goes around the clock face continually until the back up is finished.

About two weeks ago or less, i upgraded to Yosemite. Ever since i upgraded, the icon is always grayed out and never spins around. The Time Machine still creates backups, according to the pull down menu, where it gives the day and time of the last back up to Time Capsule. I am wondering why the icon doesn't spin, is it an issue with Yosemite , or is it a problem related to my particular computer?