unusual Online Armor warning

A few days ago my computer started installing Excel every first time I opened an excel sheet after turning on my computer. Online Armor would warn me about it. I just got a similar looking warning for outlook I think. I have attatched a screenshot. Should I let warnings like this pass, or should I block them? Also, what might I have done that causes Excel to have to install every time I turn on my machine. My other office products don't have this problem.