High speed I/O connection for USB devices?

twclub

When I plug in new external harddisk into my PC recently, it detects as new hardware for every time and ask me to use high speed I/O for connection?
What does it mean? It does not happen before. I though all USB plug devices are already in high speed mode.

If not, How to check which USB I/O is high speed or low speed and then use high speed USB I/O ah??

Anyone has idea?? pls pls... thx.