I am using a rooted NOOK Tablet with Android Gingerbread, and am installing an application from an email. I am using the NT Hidden Settings application to enable the installation of apps from unknown sources. I check the box and click OK knowing the dangers of 3rd party applications. I go back to the email, click the attachment, and when I hit the installation screen, after I had just checked it, it says install blocked. I returned to the setting and the check box I had filled in was now empty again, and I am caught in the loop forever. What can I do to make the app install?

  • Is your tablet rooted?
    – Irfan
    May 28, 2013 at 6:14
  • Usually that shouldn't need a separate app to enable unknown-sources. Have you checked in Settings->Applications for the corresponding checkbox? Sometimes it also hides in the Settings->Development section. Maybe it's just the fault of your "NT Hidden Settings", e.g. that it doesn't save your changes.
    – Izzy
    May 28, 2013 at 7:10
  • 1
    @Izzy The Nook tablet doesn't expose that setting out of the box.
    – Dan Hulme
    May 28, 2013 at 9:43
  • 2
    Oh -- another "closed environment" (or "apple-ish Android"). Well, that leaves at least the possibility to use adb install some.apk, which doesn't require that setting to be enabled (see Is there a minimal installation of ADB? for how to get ADB working)
    – Izzy
    May 28, 2013 at 10:35

1 Answer 1


As I wrote in my above comment, one way would be:

  1. Get ADB working on your computer (see: Is there a minimal installation of ADB?)
  2. Download the .apk file to your computer
  3. Switch on USB Debugging on your device, and then connect it to your computer via USB (order is important here: first enable the option, then connect)
  4. Use adb install <file_name.apk> to install the app

For subsequent installs, you of course can ommit the first step, as ADB should already be set up then :)

Alternative approach (untested):

  1. Install some terminal app on your device (e.g. Android Terminal Emulator)
  2. Save the .apk to your SDCard
  3. Start the terminal app, and run pm install </path/to/filename.apk>

Again, the first step is only needed once. I've not tested that second method, so I'm not sure whether it requires root or the "unknown sources" option. As adb install only seems to be a wrapper to pm install, the latter is not that likely.

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