Sorry for the lack of details. I was trying to drag and drop files from the pc to the tablet, while connected with the usb cable. I tried mp4, avi, mkv and wmv files. The first 3 always gave me the same error messages whether i dragged and droped the files or tried to copy and paste the files onto the sd card. It would say file unsupported. A program I used on windows though shows the type of container, and audio and video codecs of the particular file. In all instances according to the user manual, they are all supported. When taking out the sd card and placing it directly in the computer, I was able to transfer the files, and play them (sort of). Then I found the wmv file. That file was able to transfer. On a hunch, I changed the .avi, .mkv files to .wmv. After doing that the files transfered via usb. Not sure why only .wmv is able to transferred, but that solved the problem. The second problem though was some of the video files did not play audio, until I downloaded a video app that allowed me to use software decoding to play the audio. Again, not sure why supported file types would give me such problems, but, that little work around seems to do the trick.