Why do I get a blinking "bu59" when uploading 1 image to my computer.

[mingdurga]

Uploaded 10 images one hour earlier with no problems,  now this blinking message.    What does it mean and how to correct.

Also get  the number 592 next to the blinking bu 59.

Canon EOS D 50   /  computer is iMac 2015 with latest version Yosemite. 

Thanks.

[TCampbell]

I think you'll find it's supposed to say "busy".

If you're leaving the camera connected to the computer and there is any software on the computer capable of doing tethering, then it may be that the computer software has taken over camera control.

For example, when I do astrophotography, my tethered camera constantly says "busy" (that's it's way of saying "don't try to control me locally... I'm under control from another source").  

The busy message should go away when you disconnect the USB.