Today I will explain the differences between scans in Drive Genius 3. I spoke with a customer today regarding an issue with an external hard drive attached to his iMac. When Drive Genius 3 is installed on a mac, DrivePulse (an early-warning system) is automatically enabled. DrivePulse discreetly monitors all attached hard drives, checking them periodically for hardware issues that may evolve into larger problems which could result in data loss.
For this customer, DrivePulse reported a critical warning on their external drive that he was using for a Time Machine backup. The warning stated there were 2 bad blocks on the drive. He ran a scan and it came back clean. I asked him to run a extended scan to find the bad blocks. The regular scan does a read-only scan to find bad blocks whereas a extended scan will verify the ability to read and write from each block. The extended scan on a 1TB drive does take a lot longer to run but is a good test to run if a drive is suspected to be bad. When the scan finished and found errors, he asked if he could then erase the hard drive and start using it for his Time Machine backups again. This drive had found bad blocks before on a previous scan, and they had Spared Bad Blocks on that before, so that’s why on this second scan, we recommended the drive be replaced. He was happy for the advice and also glad that Drive Genius 3 found and noted his problem before the drive quit all together.