Please, does anyone know how to delete sensitive files, photos, and videos on MacOS M1 so that NO expensive or whatever recovery app will ever be able to recover them anymore?
I don't want to only delete them from the trash can; I want them off the hard drive or Mac. That is, without factory reset and/or wiping my Mac.
Thanks for your help!
You cannot get there from here.
If FileVault is enabled, then unless someone has the encryption key, they cannot get to your files, nor your deleted files.
If you are using an SSD (or NVMe storage), then it is non-trivial to insure that the files you deleted have all been eradicated. An SSD/NVMe write ALWAYS goes to a newly allocated pre-cleared block. If you think you are writing overtop of a file, it is actually allocating new blocks, writing to those blocks, then remapping those blocks so they have the same logical block number as the blocks you thought you were overwriting.
The blocks you thought you were overwriting are moved into the garbage collection queue to eventually be pre-cleaned for re-use.
But pre-cleaning in hardware is done in physical regions of the SSD. So before your old block on the garbage collection list is pre-cleaned, ALL the other blocks in his region must make it to the garbage collection list, OR the hardware must do a read/write of blocks in the region that still have good data and write them to newly allocated blocks, so the other blocks are now on the garbage collection list.
When all the blocks in a physical region are on the garbage collection list, the hardware will do a pre-clean on that physical region, and put all those blocks on the available queue for the next available write.
NOTE: most SSD/NVMe drives have gigabytes of spares in the available queue so that the SSD/NVMe drive can avoid doing a lot of read/writes to get an entire physical region onto the garbage collection list in order to fill up the available queue. So some or all of your file data could be sitting on the garbage collection queue for an extended period of time. Which is why it is a good idea to enable FileVault so that at least your encryption key is needed for someone to access your storage.
This also means that if you were to write zeros or a random nonsense pattern to the file's allocated storage, each write would not touch the original data, and would just shorten the life of your SSD/NVME. It shortens the life, because SSD/NVMe storage has a limited number of writes before the block deteriorates. The writing is rater destructive to the SSD/NVMe storage. The sparse also provide replacements for blocks that are no longer writable.
So basically, you cannot get there from here.
The good news is that Apple enables TRIM support which means when you delete the file, Apple tells the SSD/NVMe storage that this range of blocks can be put on the garbage collection queue, which improves the chances that your file will sooner rather than later be pre-cleaned by the hardware and put on the available queue.
If you have government sensitive data that must not be recovered, then melting the storage device into slag is the surest way to make sure it is no longer readable. Or reformatting a FileVault enabled volume so that the old encryption key is destroyed, and the encrypted data is less likely to be decoded.
You cannot get there from here.
If FileVault is enabled, then unless someone has the encryption key, they cannot get to your files, nor your deleted files.
If you are using an SSD (or NVMe storage), then it is non-trivial to insure that the files you deleted have all been eradicated. An SSD/NVMe write ALWAYS goes to a newly allocated pre-cleared block. If you think you are writing overtop of a file, it is actually allocating new blocks, writing to those blocks, then remapping those blocks so they have the same logical block number as the blocks you thought you were overwriting.
The blocks you thought you were overwriting are moved into the garbage collection queue to eventually be pre-cleaned for re-use.
But pre-cleaning in hardware is done in physical regions of the SSD. So before your old block on the garbage collection list is pre-cleaned, ALL the other blocks in his region must make it to the garbage collection list, OR the hardware must do a read/write of blocks in the region that still have good data and write them to newly allocated blocks, so the other blocks are now on the garbage collection list.
When all the blocks in a physical region are on the garbage collection list, the hardware will do a pre-clean on that physical region, and put all those blocks on the available queue for the next available write.
NOTE: most SSD/NVMe drives have gigabytes of spares in the available queue so that the SSD/NVMe drive can avoid doing a lot of read/writes to get an entire physical region onto the garbage collection list in order to fill up the available queue. So some or all of your file data could be sitting on the garbage collection queue for an extended period of time. Which is why it is a good idea to enable FileVault so that at least your encryption key is needed for someone to access your storage.
This also means that if you were to write zeros or a random nonsense pattern to the file's allocated storage, each write would not touch the original data, and would just shorten the life of your SSD/NVME. It shortens the life, because SSD/NVMe storage has a limited number of writes before the block deteriorates. The writing is rater destructive to the SSD/NVMe storage. The sparse also provide replacements for blocks that are no longer writable.
So basically, you cannot get there from here.
The good news is that Apple enables TRIM support which means when you delete the file, Apple tells the SSD/NVMe storage that this range of blocks can be put on the garbage collection queue, which improves the chances that your file will sooner rather than later be pre-cleaned by the hardware and put on the available queue.
If you have government sensitive data that must not be recovered, then melting the storage device into slag is the surest way to make sure it is no longer readable. Or reformatting a FileVault enabled volume so that the old encryption key is destroyed, and the encrypted data is less likely to be decoded.
Your M1 is encrypted regardless of using FileVault.
Erase All content and settings will delete the decryption keys. Short of someone with a quantum computer getting hold of it, nobody could guess the encryption keys in your lifetime.
There is no capability to secure erase any drive. There was a possibility to secure erase an HDD. There is absolutely no guarantee it will actually be unrecoverable.
Macintosh HD is a name. It isn’t a description. I don’t think it is possible to have an HDD in an M1 Mac.
I think you can secure erase an external HDD, but as noted above, zero guarantee.
If you do not want to erase all content and settings, enable FileVault with a strong password. That way the drive will not automatically decrypt when you log in and you must know the login password to decrypt the drive.
FileVault is "Whole Disk Encryption"
Your entire boot disk is encrypted. All your data, your trash, your preferences, you pictures, documents, files, folders, EVERYTHING is encrypted with FileVault.
My explanation above still stands. You cannot get there from here, because your system is using SSD/NVMe storage.
FileVault is the best way to make sure only you can see your files, and partially deleted files, should you loose control of your Mac because it was lost, stolen, or confiscated by authorities.
Hi,
Thanks very much for responding. My question does NOT have to do with erasing FileVault. My inquiry is about how to erase the contents of the trash can so that they're not recoverable anymore. Is the trash can contents part of FileVault?
theconstantgardener wrote:
No, my MacBook Venture says Macintosh HD.
If you're seeing that on the Desktop it's just the name of the volume. There's Macintosh HD and Macintosh HD - Data. M1s don't use HDD drives only SSDs.
FWIW, if your Mac uses an SSD the chances of anyone recovering a file is virtually zero.
No, my MacBook Venture says Macintosh HD. I would like to know if there's a way to delete files so they are unrecoverable.
Thanks!
Secure Emptying the Trash
