I’m curious what the difference is. My understanding is that the “Quick Format” doesn’t really format the hard drive and just tells the computer the space is unused even if there are things there which will be overwritten.
However what happens when you uncheck that box? Is data recoverable at all if you format with it unchecked? Is it safe to do this format and sell the external HDD?
No, no no. if you format the drive, data is definitely recoverable I’ve done it. If you’re going to sell a drive you want to use a DOD or NIST wipe based on the type of drive.
If you want to re-use a drive, or sell it, there are only certain ways to ensure it has been safely “wiped”.
If it is a traditional, spinning-rust drive, you can either,
- Conduct a zero-fill pass. Ideally three. But anything more than one pass is likely overkill.
- Encrypt the entire drive, fill it with random data, then throw away the encryption key.
Neither method will touch reallocated “bad block” sectors that have been taken out of action due to corruption or damage; these sectors may still hold recoverable fragments of data. But at the same time, these sectors also cannot be easily read.
If it is a newer SSD or flash drive of any kind, you can
- Engage the drive’s self-wiping feature. This should also wipe any reallocated sectors that can still be written to, ensuring a near-total wipe of the drive.
- Encrypt the entire drive, fill it with random data, then throw away the encryption key. As with a spinning-rust drive, this will not touch any reallocated sectors.