Wow, I've never had it take more than a couple hours to finish up all of its compression. Then again, I've never tried to feed it 250 CDs in a single sitting, I always did them in small batches of fewer than ten at a time.

Does the user interface (main menu) still work, and does it show the little turning gears?

Note that it should be reasonably safe to power-cycle the unit, even it it's encoding, if you think there's something going screwy with the software.