Wow! I'm sorry to read that so many folks still have this problem.
I actually blundered into a fix on my own. Hopefully I can recall the steps as I know nothing about the inner workings of computers.
I tried updating drivers.
I spent at least 1/2 hour on the phone with the Geek Squad who assured me there was no card reader driver installed on my computer.
Then I followed the steps suggested by the Microsoft Engineer. As some have posted, it worked until I had to reboot the computer.
Frustrated because I knew that it had to be a problem with upgrading from 8.0 to 8.1, I systematically searched through my Device Manager for something that sounded like a driver for a card reader.
I finally found it listed I believe under Universal Serial Bus Controller. This was not where the Geek Squad searched. Of course following the Microsoft Engineers steps may have reinstalled the driver....I have no idea if it was there all the time or not.
I visited the driver's website and found they had a patch for Windows 8.1. Mind you this was only a patch not an update. Hence the reason updating drivers did not work.
Installed the patch, rebooted and it has worked ever since.
Maybe if you can't find the driver under Universal Serial Bus Controller, you should follow Microsoft's suggestions then check again.
I sure hope this helps someone. Since I primarily use my computer for photography, it was a nightmare for me.