What TRIM does and why it matters
TRIM is a command the operating system sends to the SSD to mark data blocks that the file system no longer uses. The drive's controller can then erase those blocks in the background ahead of time, which keeps write speeds high. Without TRIM, the controller must shuffle data around on every write, and performance slowly sinks over months.
Windows has supported TRIM since Windows 7 and enables it by default for both SATA and NVMe drives. In practice you check it when an SSD feels progressively slower, after cloning a disk, or when a monitoring utility reports TRIM as disabled. On a healthy Windows 11 install, it almost never is.
Checking and enabling TRIM from an elevated prompt
Press Win+X and choose Terminal (Admin), then run the query command. Windows 11 answers with one line per file system — NTFS: DisableDeleteNotify = 0 means TRIM is enabled for NTFS, and the same applies to the ReFS line if one appears. If you ever see a 1, turn it back on with the set command and reboot.
- fsutil behavior query DisableDeleteNotify — shows the TRIM state for each file system.
- 0 means TRIM enabled, 1 means disabled; Windows 11 normally shows 0 everywhere.
- fsutil behavior set DisableDeleteNotify 0 — re-enables TRIM for all file systems.
- fsutil behavior set disabledeletenotify NTFS 0 — targets one file system only.
- The check needs an elevated prompt: Win+X → Terminal (Admin).
Scheduled optimization and manual retrims
Type Optimize Drives in Start, or run dfrgui, and check the Media type column: Windows knows an SSD from an HDD, and for SSDs the Optimize button sends a retrim instead of a defragmentation. Scheduled optimization is on by default and runs weekly. That keeps the drive informed about free blocks without you doing anything.
Do not defragment an SSD deliberately — it adds wear for no benefit, and Windows already handles the rare cases where it makes sense, such as volume shadow copies. Recheck TRIM after a disk clone, a fresh Windows setup or a motherboard swap. Clean installs and firmware quirks occasionally leave it disabled.
Questions and Answers
How do I check if TRIM is enabled on my SSD?
Run fsutil behavior query DisableDeleteNotify in an elevated Terminal. NTFS: DisableDeleteNotify = 0 means TRIM is enabled; 1 means it is disabled.
What does DisableDeleteNotify = 0 mean?
It means the OS will send delete notifications, which is TRIM. Windows sets this value to 0 by default on every installation, so a 1 usually indicates a policy or a tool changed it.
Is it safe to run Optimize on an SSD?
Yes. On an SSD the Optimize Drives tool performs a retrim, not a defragmentation, so it does not wear the drive. It runs automatically on a weekly schedule by default.
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