External disk failure (?)

Hello friends. Please forgive my rudeness but I’m trying to solve a really weird problem. I’m using openSUSE 13.2 KDE on my laptop, with everything updated. It works almost flawlessly, except a little (big) thing that drives me nuts.

I have an external USB HDD which I keep connected almost all the time (for automated backups etc.). So, what is my problem? If this disk is not used for a while, it spins down. So far, so good. But, if it is spinned down and I try to access it via dolphin, it doesn’t work. On other distros, the system would just hang for a second while the disk spins up. But with openSUSE everything freezes, then the screen contents get corrupted, it all turns to black and I can’t do absolutely anything besides being forced to press the power button. Sometimes the very same thing happens when I’m using another program that tries to access the filesystem (say GIMP), even if I want to go to a location different than the usb HDD. As long as it is connected and spinned down, I’m bound to face a freeze. If it’s not connected at all, everything works as it should.

The easiest thing would be to connect and disconnect it at will but that’s not an option since then I would have to change my work case and my backup schedule. Besides, I’ve confirmed that it works on other distros so any help would be much appreciated.