USB an CD at the same time, crash?

@Stefan > Can you elaborate a bit more on how you cause the crash please (e.g. your setup, how everything is connect, how you are switching between sources, when exactly the problem occurs).

It happened again last night.. I've been play whit usb almost all night.. But at the end i wanted to play a cd. Players and mixer are linked (cdj 2000 and djm 900). I was playing a usb track from player 1 (the player whit usb stick). Then i inserter a cd i player 2. It started to play then it just stopped and a error message was shown on the display. After that it was impossible to insert a cd. I restarted the player, pulled out the link. Nothing helped. Never had these problem whit cdj 900.. 

@Stefan > Does this problem occur with the same CD or a range of different CDs?

Last time it happened it was whit another cd.. And it happened when i rented them out to another dj also.. As i said, this was never a problem whit the cdj 900.. It must be possible to use both usb and cd at the same time, or?

you're not alone, there seems to be issues with this between here and the serato forums too, people trying to use USB then cd and the players are locking up, can't be used unless you unhook ethernet, etc....  I will do some testing to later