A small red triangle I the right bottom corner with a "1".

[Clasgoran]

Later a red square wit the text: "A low-level exeption occured in".  And below that "(DeviceController)"

[Ann Bens]

...so we dont have to download unknown files: we help you, you help us. Thanks! 

[R Neil Haugen]

Sometimes warnings appear that are cautionary but don't mean a real problem has happened. Does anything seem broken after this appears?

Neil