I recently helped a customer who was running a scan using Data Rescue 3 on his external hard drive that was no longer mounting. His drive was 500 GB and he had been running the scan for an entire day but it seemed to be stuck at 19%. He called support asking if he should continue the scan or if there was anything else he could try. When scanning progresses slowly like in this case, it could be due to physical issues with the drive and we would recommend cloning the drive. I guided him to start a clone to a new drive that was the same size and it took a long time to finish as well but the cloning process did complete. He was then able to run a Deep Scan on this drive and recovered his data to another drive.