One of the cameras that I use from time to time is one that requires mini CD's to record and store the images.
I find it easier to pop the CD's into the drive on the CPU than to hook up the USB cord to get the images onto the computer.
Well, since I only use this camera occasionally, I tend to forget the CD is in the drive and it just sits in there.
Now, this is not a problem for normal operation of the computer or for booting up or shutting it down.
But, when I hook up my other camera by USB cord and try to transfer the images to the computer, the whole system freezes.
And I spend time trying to figure out why - the computer won't even shut down properly.
And then it dawns on me - is there a CD in the D drive slot.
I look to my left and see the empty CD case that confirms my suspicions.
After rebooting the system and removing the CD, everything works just like it is supposed to.
There must be some glitch or conflict in the programs that upload the images.
I am not going to even try to figure that one out, but I really must remember to keep those drives empty.
I would write myself a note, but I know I would just forget to look at that too.