I have 2x laptop ASUS K551LN under windows 8.1.

1) One without problem
I can read/write on any external HDD on usb3 ports

2) The other (latest BIOS 209)
- when I plug an USB key in usb2 or usb3 ports : no problem
- when I plug an external HDD (self powered, icy dock powered, inateck dock powered)
- no drive letter allocated
- when I try to eject i see the UID of the disk, not the name/letter
- when I allocate a drive letter using a partition tool (ea. diskmgmt.msc), i can see the disk, but its in RAW mode (even when I partition, format, write ntfs datas, ..using my other laptop)
- when I plug the hdd in anothe laptop, it stay in RAW.. cannot recover datas I have to remove partition

I try with different HDD / supplier, HDD docks, ..always same issues. it was working well a few months ago
I do always 'eject' before removing a disk

any idea ? I cannot use any external HDD now..