Window Pops Up & Disappears

[edups88]

So this is new...

I'm running Yosemite on my iMac. Recently, when I startup the computer, after everything loads and I'm on the desktop screen, a window flashes open and immediately closes in an instant. I can't tell what it is...? Any ideas?

 

[ApfelKuchen]

Check System Preferences > Users & Groups > Login Items (not Login Options)

 

[edups88]

Check System Preferences > Users & Groups > Login Items (not Login Options)

I did that. I have no login items...

 

[ApfelKuchen]

Then you probably also tried Safe Boot... Does it still pop up? Anything show up in Force Quit?

Etrecheck may help you track this down, since it analyzes your startups and kexts. etrecheck.com

Did you let anyone remote into your system? What about downloads from the web? For that, Malwarebytes for Mac may also be a help - malwarebytes.org