I am having some difficulty identifying a problem on Nuendo. Under the "Performance Metre" on the top row of the tools, the metre is fluctuating up and down, going into the red. The system is lagging which may or may not be the result of this but when I put my cursor over the Performance Metre, it says "Disk Cache Overload". I have searched for a reason behind this and have failed to come up with anything. Can anyone shed any light on this situation.