Updated my windows to version 8.1 and when I install the driver it asks to connect the A800 Pro and when I connect nothing happens, it does not install. When I go to windows driver see the A800 there with the problem, but the installation screen is still waiting for the device to connect. But it is already connected. I tested the USB port 3 and 2, but without success. Please Help me.

Go here and see if your drivers are updated :
http://www.roland.com/sup...?k=i&q=information

There is win 8.1 drivers out .

:-))
All the best
Jan

The new Windows 8.1 driver is out this AM.
 
http://www.roland.com/support/article/?q=downloads&p=A%2D500PRO&id=63061512
 

this worked. ;)