Desktop strange issue

[vonglower]

Hi guys,
Some times (not very often) suddenly the desktop darkens, and the menu bar and the disktop icons disappear, while the dock remains. I have to click in order to return!
What causes this thing?

P.S. Before awhile, that this happened again, I looked at the console and saw these two events:

1)**** [IOBluetoothHostControllerUSBTransport][SuspendDevice] -- Suspend -- suspendDeviceCallResult = 0x0000 (kIOReturnSuccess) -- 0x3000 ****

2)setPresentationOptions called with NSApplicationPresentationFullScreen when there is no visible fullscreen window; this call will be ignored.

But I cannot specify the exact time it happened, in order to see if any of those two messages are related.

 

[vonglower]

Hi all,
I experience almost once a week the following issue:
Suddenly the screen darkens, the desktop icons disappear. However, when I click, everything comes back to normal.
I attach two photos, one with the desktop at the time this happened last time, and one with a message in the Console (I am not sure if it is related to my problem, but I thought that it would be wise to show it to you).
Any ideas, please?

and this

P.S. MacBook Pro 13'' (Mid-2012, OS X 10.9.5)