I beg folks answering this question to stick to the point, and refrain from answers such as "why do you run encryption anyway", or "use Bitlocker instead". This question is specifically about TrueCrypt and Windows7

I have copied encrypted system drive from one 240GB SSD disk to another 240GB SSD drive by making an exact sector-by-sector copy. I know that TrueCrypt does support TRIM, at least on system drives. At this time, I would assume the target disk thinks that every sector is in use, since every sector have been written to. I tried finding a utility, which will run TRIM on all unused sectors, but it seems that I cannot find any. There has been references to ForceTrim utility on OCZ forums, but it seems to have been either deleted or locked up, because I cannot access it.


  • How do I force TRIM of all unused sectors on a system drive?

  • How do I verify that TRIM has been successful and drive indeed is aware of all unused space? How to tell, how many sectors are marked unused by the drive?

My drive is OCZ Vertex3


One simple solution to force-TRIM everything would be to create a huge file that fills up all your free space, then delete it. That should make the OS issue TRIM commands for all the space that's now free on the drive.

  • Do you know how do I test, how many blocks are marked in use, so that I could tell that they were indeed TRIM'ed? – galets Sep 25 '12 at 16:06
  • @galets: That would be a question for the OCZ forums. – surfasb Sep 26 '12 at 0:00
  • @surfasb Tried... Seems like OCZ forums are useless – galets Sep 26 '12 at 3:43
  • For Windows: Note that the Samsung Magician software (that ships with, e.g., the 840 series) also has a feature that does this (it's disguised as "Optimize Performance", but this is what it does -- it's specifically for systems without explicit TRIM support). I believe the feature can be used on any drive, it doesn't have to be a Samsung product. – Jason C May 27 '14 at 20:01

I found an interesting program here! Quote from the "review":

It is a very simple and completely safe utility that merely creates a few large file entries on the ssd in order to fill the drive's free space, and then deletes them. This, assuming TRIM is enabled on your system, will cause your OS to issue trim commands to the ssd to cleanse the space those large files took up (Specifically, all the free space). After running this, the ssd should be managing this cleanup completely on its own in the background, and may take a few minutes. You really have no way of knowing, other than just coming back later and running a benchmark to see if your write performance has increased

  • 1
    Also: CCleaner does same thing, and since it's a mature trusted product, maybe it's worth using just that. Can not be too careful these days – galets Nov 11 '13 at 17:32

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