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Try to look at this path: /data/app/ (use some root browser, or file manager) , then try to find file with extension .odex it will be at this format [com.nameOfTheAppOrVendor.something.odex] or [org.nmeOfTheAppOrVendor.something.odex] for example app: WpsWpaTester is here stored as [com.tester.wpswpatester-2.apk] and it's odex as [com.tester.wpswpatester-2.odex]...when you patch WpsWpaTestes the Lucky patcher created that odex file ([com.tester.wpswpatester-2.odex]).. So you have to find file [com.NameOfTheAppYouWantToInstall.something.odex] and manually delete it. Each normall app will have there one file with .apk extension, every app you have patched with LuckyPatcher will have there two files, one with .apk extension and one with .odex extension. An probably when you uninstalled that app, system deleted only file with .apk extension and file with .odex extension is still there, so that's why system can not install that app again (it thinks that the app is already installed).