Ability to move app to SD is broken

I've looked around on here and found a few posts related to allowing app to SD functionality, but [I still think] I've got things set up correctly. The app asks some users if they'd like to install the app to SD on update/initial install, but won't allow them to move it to the SD card later. On the phone I us开发者_运维知识库e (Android 2.2.1), I have the same issue. On one of my test phones (Android 2.2), I can move it to SD and back to the phone just fine.

This is my manifest file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.badwaterstudios.ProfanityCandy"
    android:versionCode="18"
    android:versionName="2.1.2"
    android:name="ProfanityCandy"
    android:installLocation="auto" > <!-- SDK 8+ only, allows install to SD -->

    <uses-sdk android:minSdkVersion="4" android:targetSdkVersion="8" />

Thanks in advance for your help!

One reason why the application can't be moved to the SD card is if you have copy protection turned on in the publishing options(seen while publishing/updating your app). Turn this off to allow moving app to the SD card.

Also see the article at http://developer.android.com/guide/appendix/install-location.html about Applications That Should NOT Install on External Storage