I recently had a problem that prevented updating any application installed on the SD card. When trying to update the application in the market, the update failed and the following message was given as detailed error:
Couldn't install on USB storage or SD card.
A possible workaround is to move the application back to the phone, update it, and then move it to the SD card again.
How can we fix the error permanently?
A fix I've found and that works is to mount the SD card on a PC, open the *.android_secure* folder and delete a file named smdl2tmp1.asec.
It seems that it's a leftover file from a previous (failed?) installation/update that prevents another update to run correctly.
After moving the app off the SD card to the phone I didn't even have to take the SD card out, it updated fine. Check with following links
2: http://www.newbiehelper.net/2011/05/solve-install-on-usb-storage-or-sd-card.html
You can find the file smdl2tmp1.asec in the folder /mnt/secure/asec/. As Dario said erase it :)
