What TRIM Does

Flash memory cannot overwrite a cell in place. A block must be erased before it is written again, and erasing is slow. To keep writes quick, Windows tells the SSD which blocks belong to deleted files, using a command called TRIM, and the drive erases them in the background when it has a quiet moment. On a hard disk a deleted file sits until something else needs the space. On an SSD with TRIM on, the drive clears it on its own schedule, which may be minutes.

Windows 10 and 11 have TRIM on by default for any drive they recognise as an SSD. You can see whether it is on for a given drive in DRE Pro under Drive Health.

What That Means For A Deleted File

The window to recover deleted files from SSD drives is short and its exact length is unknown, because it depends on when the drive decides to run its clean-up. Some drives trim within seconds. Others wait for idle time. Once a block has been trimmed, reading it returns zeros. The file is not hidden, it is gone, and no software recovers zeros.

So the advice is blunt. If you deleted something on an SSD and want it back, do not restart in the hope that it helps. Scan now. A Quick Scan takes minutes and reads the index first, which still lists the file even if its blocks have started to go.

Where TRIM Does Not Reach

• Many external SSDs and USB-C drives in cases that do not pass TRIM through at all. These behave more like hard disks for recovery.
• A partition that was deleted or lost rather than its files. The data blocks were never marked for trimming. Lost Partition Recovery looks for these.
• A drive that was moved to another computer before Windows could trim it.
• Files replaced by a save in place, where the old version still sits in a block the drive has not reused.

Honest Expectations

In those cases a Deep Scan or RAW Scan on the SSD finds files by contents the same way it does on a hard disk. People search for TRIM SSD recovery hoping for a tool that reverses TRIM. No such tool exists, in DRE Pro or anywhere else. A trimmed block has been erased by the drive's own controller and the data is not physically present any more. What recovery software can do is find everything that has not yet been trimmed and show it to you quickly, before the drive gets to it. The sooner the scan, the more there is.

Scanning An SSD With DRE Pro

1. Open Drive Health for the drive. Note whether TRIM is shown as enabled and whether the status is Healthy.
2. Run a Quick Scan straight away. It reads the index and lists recently deleted files with their names.
3. Preview what it finds. A file whose blocks were trimmed previews as blank or fails to preview, and is marked Overwritten.
4. Save the Good files to another drive at once, before running anything longer.
5. Then run a Deep Scan for anything the Quick Scan missed. Pause and resume it under Saved Scans if you need the computer.

Failing SSDs Are Different

A hard disk usually warns you with noise and slowness. An SSD tends to work perfectly and then stop, or drop into a read-only mode where nothing can be written. If Drive Health shows Warning or Failing, or the wear level is high, do not keep scanning. Make An Image Of A Drive copies it once to a healthy drive, and Scan This Image does the rest. If the SSD is not detected at all, that is a controller or firmware problem and software cannot reach past it.