Gear-like symbol on Desktop after Sleep

I have a MacBook Pro (15 inch, early 2011) OS 10.10.5. The past two days, after the MBP goes to "sleep", there appears at the more or less center of the screen a small (less than 1/4 inch), white, round gear-like symbol. (The attached JPG gives an idea, but the actual thing is much sharper, more gear-looking.) The only way I can get rid of it is by turning off the machine, and to do that, I have to hold the ON/OFF button down longer than usual (maybe ten seconds). I have run ClamXav, which found nothing. I will greatly appreciate any ideas! Thank you.

What happens if you click on the gear like symbol or right click on it?

I am embarrassed to say that it's gone. I have put the laptop to sleep (Apple>Sleep) a half dozen times today, as well as allowed it to go to sleep on its own several times, and the gear symbol no longer appears. The only thing I did since writing my first post is, I wandered around System Preferences looking for some option I might have selected which I should not have done. The only item I found I could not explain was at "Security & Privacy>Location Services" where Calendar.app, Weather, and Maps.app were checked to "allow the apps below to determine your location". I don't remember checking those, and I can't think of why I would have. But I unchecked them. And since then, no gear symbol. If it does reappear, I will return here, and answer your question. In the meantime, I thank you and apologize for having apparently wasted your time.