I had this same problem a week ago, what it you have somewhere is a corrupt file or files. The only way you can get around this is to reload a previous back up, prior to the error happening. problem will be that you don't know when the error happened. I tried a couple of different backups and the only one that worked was one from a year ago, so i have lost a years worth of data. Luckily for me i keep a hard copy of all my new details. It will take me months to key it all back in, but at least i know i haven't lost everything. The key in the future is to make regular backups and keep them on a separate hard drive.