I'm getting the following installation error on a few of my apps when trying to update them:

"Installation error - Unknown Reason - 18"

Any suggestions? I'm running CM6 on a Motorola Droid.

  • I've had the same issue on my HTC Desire (with the default OS install), with the error "Couldn't install on USB or SD card" when trying to update apps that had been installed to SD. Removing .android_secure/smdl2tmp1.asec as per Jan Willem's post fixed this. I'd suggest retagging this, since it doesn't just apply to cyanogenmod or rooted phones. Jun 9, 2011 at 21:36

2 Answers 2


Removing smdl2tmp1.asec is the solution, but because "su" will lead to "permission denied" if you don't have a rooted phone, and because the /mnt/secure/ appears to be empty, removing the file can be hard.

Alternatively you can do the following:

  • connect the phone to a computer with USB
  • mount the SD card as a disk drive
  • remove .android_secure/smdl2tmp1.asec
  • +1 for the idea to mount SD as disk drive!
    – slolife
    Apr 14, 2011 at 23:47

Apparently the problem is with apps installing to the SD card. Running the following command in the terminal fixed the problem for me:

rm /mnt/secure/asec/smdl2tmp1.asec

You must log in to answer this question.

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