Player Freezes on Refreshing Database

I recently formatted and then transferred a large number of songs to my sansa clip and now when I turn it on, it gets stuck halfway through refreshing database. I tried hard resetting it, which didn’t work. I also tried forcing is into msc usb mode and formatting from the computer but when I try to connect it it just flashes the lock symbol and doesn’t connnect. I’m assuming this whole problem is caused by transferring a corrupt/unreadable file. If so is there anyway to find which one it is? Could somebody please help?

When you try to force MSC mode, start with the Clip OFF and slide the power button down to HOLD position (orange showing).  Since it’s OFF, you won’t get the lock symbol and it should connect in a few seconds.