Deleting files and formatting disks just got a whole lot more dangerous!
Back in the good old days1, before fast SSDs, and multi Terabyte disks, if you accidentally deleted a file, you could be fairly confident that you could get it back. In classic Mac OS, it wasn’t uncommon to have Norton UnErase running every time your Mac shut down, to show a list of deleted files for you to optionally restore.
Not to be overdramatic, but those days are pretty much gone.
What changed?
With modern disks you cannot run a quick undelete to recover files. In fact, even powering on a disk after you deleted some files could actually destroy those files permanently.
For various technical reasons2, disks now need to keep track of which sectors are in use. This allows them to carry out background “housekeeping” tasks to keep the disks running smoothly. Modern operating systems issue a TRIM command when you empty the recycle bin, to let the disk know which sectors are no longer in-use. The disk will then erase those sectors and add them back to the pool of available sectors.
An example of some disks that likely wipe out deleted / formatted data
- Western Digital (WD) My Passport drives from 2TB+
- Seagate external drives from 2TB+
- SD / microSD / SDHC / SDXC cards
- m.2 SATA SSDs
- m.2 NVMe SSDs
- SATA SSDS
- iPhones / iPads / Android phones & Tablets
- + Lots of other variations of the above!
If you’re unsure, you should safely unplug the disk ASAP, and get in touch. We’ll hopefully be able to let you know the chances of recovery.
Conclusion
If you accidentally delete some files, or accidentally format a modern disk, your chances of recovering those files are greatly reduced. Act fast and turn off the disk ASAP. You may prevent the data being lost for good, but it will likely need to be recovered by a professional. If that happens, you must let them know the situation, so they can handle it properly.
Good luck!
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