I am not sure if this app works. Can someone please help me? My phone is new and in its warranty period so I can't root it yet. I tried this app but I am not sure if it actually did something. Unlike the other famous app on the PlayStore for fstrim, it doesn't require root access which is quite incredible.

  • How would the testing of this app by any random user on the internet help you specifically? Why wouldn't you reach the developer with your problem directly? It would certainly be more advisable than a total stranger with almost certainly different equipment, needs and techniques, providing a questionably-appropriate response.
    – wbogacz
    Jun 8, 2019 at 17:35
  • I don't know enough about trim commands and I don't think the developer would be honest about how their app is fake and doesn't work at all (or does something other than promised). That's why I think people who don't earn profit off that app will give a more honest review.
    – Sbeve
    Jun 9, 2019 at 6:50

3 Answers 3


AFAIK, only apps running as root (UID 0) (1) or system (UID 1000) (2) or with android.permission.MOUNT_UNMOUNT_FILESYSTEMS (3) can do fstrim. But third party apps can neither get UID 0/1000 (without rooting phone), nor the said permission is for third party apps (4).

Also manually sending FITRIM ioctl with fstrim command requires at least capability SYS_ADMIN (5), which is almost root if not full root.

The app you have mentioned asks for permissions CLEAR_APP_CACHE (delete all apps cache data) and KILL_BACKGROUND_PROCESSES (close other apps). So it's quite evident what it must be doing to give a feel of lag-free experience.

PS: You don't need to run fstrim manually in most cases, OS can handle this. See this answer.


I highly doubt it. I use an app called Trimmer which requires root to trim /cache, /data, /system. I installed this app & ran only selecting cache, but it shower trimeed cache & data. I ran a logcat, did not catch anything. So most probably it is a snake oil or at best it clears your cache.

  • +1 snake oil 👍 Oct 22, 2019 at 16:14

Here is the link how this app works you might not understand the language its English title is LagFix Trimmer to cure the machine without root | Easy Android Click here

  • rooting is not bonded to unlocked bootloader, as you stated. theoretically you can root with locked bootloader via exploit (KingRoot was a good/bad example the older days), while locked bootloader just prevent devices from running unofficial firmware (and as a side effect, protecting userdata from unauthorized access)
    – alecxs
    Jun 8, 2019 at 13:31
  • 1
    @alecxs thanks for correcting me as i have never seen anyone to root their phone without unlocking bootloader but in my case my phone won't rooted with kingroot but after unlocking bootloader i flashed pre rooted rom so i was thinking it was the bootloader who prevents from not rooting the phone
    – K S Maan
    Jun 9, 2019 at 0:25
  • What do I do? The language is not understandable.
    – Sbeve
    Jun 17, 2019 at 22:39

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .