Problem with sound from mediabay

Hello everyone, I am new here and hope someone could help me…

I use Cubase 5 (original, I know is old…) on iMac, my problem is that sometimes, apparently with no reason, the sound coming out from the mediabay is mute… It happens every few months, and I always solved it with the control room preferences, but this time is different… Basically when it happens, you see the samples list and the when you click on a sample the wave appear under the list but with no sound coming out, you switch off the control room and everything get normal, but this time there is no wave when i click on the samples, so it lists all the libraries, but not the wave and is without sound… Anyone know what it could be? I am a Steinberg user since ever but really getting fed up with it… spent lot of money on original softwares (not only this one) but all the new software are much better… Cubase is still too heavy and with so many bugs, and don’t tell me is because I use an hold version, it had problems since ever and is a very heavy software… Thinking to change DAW, but for the moment is the only software I have so hope someone could help me to solve this situation… Thanks everyone

I use a Focusrite saffire LE with OSX 10.6.8 - Intel core 2duo -Ram 8gb DDR3