Install failed: the package is already installed
INSTALL_FAILED_ALREADY_EXISTS
An app with the same package name is on the device and the install was not told it is allowed to replace it.
Why it happens
An ordinary update carries a replace flag. Without it, the system treats the install as an attempt to create a package that already exists and rejects it.
How to fix it
1. Turn on Replace existing
It is on by default in Universal Installer; if you turned it off, this is the error you get back. This is the one case where Replace existing is genuinely the answer.
2. If it still fails, it is not this error
A downgrade or a signature mismatch can surface with similar wording. Check the version number and the source of the file — the two pages linked below cover those.
Also shown as
- A conflicting version is already installed
- package conflict