First, if many people crash or encounter other situations when installing the program after opening APP2SD in Android2.2, they will prompt "Application not installed" when installing the program again, and the installation program will fail.

Solution: Connect the computer in storage mode and find it. Android_secure folder under the SD card directory. There should be a smdl2tmp 1.asec in it, or a file with other names. In short, it is obviously different from the normal program naming format. Delete it, reinstall the software and see if it works.

2. Open Settings-Manage Applications-

When viewing the programs on the SD card with the program management provided by the system, some programs have no color icons. It turns out that these softwares without icons are at work. These software without icons are incomplete software data that have not been installed or uninstalled correctly before. If you install them again, you will report an error. Now we use the software management provided by the system to uninstall them clean, so there will be no mistakes in reinstalling the software.

Third, some software signatures have changed, so they can't be cover the installation. Just remove and reinstall a new version.