Audio device has been removed - cannot record in Logic Pro 9 anymore

I have just started getting the following message: "Error code 2 was returned by audio driver. Audio device has been removed." Can someone help me with this? I thought I could perhaps solve this problem by going to the latest Mac OS - El Capitan vs 10.11.2 but this did not work...still having same issue. Also, uninstalling/installing the driver software did not solve the issue although it did start to record for about a minute and then gave me the same message.