How do I uninstall the LINE app (third party app)? At my sister's suggestion, I installed the LINE app in my Galaxy S3. After a while I decided I didn't like it, so I want to uninstall it. Weirdly, when I open Settings > Application manager, there is no option to remove application, only "Uninstall update", which restore an earlier version of the app. The same situation when I open Google Play, the "Uninstall" button only uninstall the updates and restore an earlier version. Same luck with trying an uninstaller . I also read that some application may prevent uninstallation by setting itself as Device Administrator, but I check my Device Administrators and LINE isn't listed.

I only observed this behaviour before for system apps or apps that got installed by my carrier, but LINE certainly isn't such app, I installed it myself. How could they have uninstall restriction, and how can I uninstall it?
Seems like 'Line' has been converted to a system app. You can convert it back to a user app and uninstall it if you have root permissions by using apps like App Uninstaller or System App Remover.

Otherwise you can disable it after uninstalling updates. "Disable" button can be found besides the "Force Stop" button under Settings &rarr; Apps &rarr; [offending app]

Else restore your phone (preferably from a Nandroid backup if you're rooted with a custom recovery). Even a factory reset might work.