How do apps installed via Mobile Device Management behave? What happens if a user installed an app manually (from AppStore or Enterprise App) and later on MDM tries to install the same app?


Does MDM app installation fails (because the app is installed already)
Does MDM overwrite existing app?
Does MDM request whether to overwrite?


MDM has a notion of "managed apps". These apps are installed through MDM and MDM can remove them. Mainly, I am interested in this question to understand whether these apps could be removed through MDM later on.

If MDM overwrites existing app (with or without user acceptance) then these apps will be managed and could be removed through MDM later on. If MDM fails to install them than they won't be managed (can't be uninstalled).
Having an MDM doesn't change the permissions and app deletion behavior on iOS so it only facilitates getting a redemption code onto the device.

What really matters is who signed the app. If the app is signed from Apple - then it doesn't matter if it came from iTunes, iCloud restore, MDM or Apple's app store. A user can either delete all apps or no apps based on the iOS profile in force.

Now, for enterprise signed apps (or developer signed apps), you can tie a signing certificate or trust chain to a configuration profile and ensure that apps signed by that cert get deleted when the profile is deleted.

So a user can decide to remove one app or remove all apps or remove the profile. But the user can't remove the profile and have the apps remain.

This is a nice general overview. If you select a particular MDM solution (Casper, AirWatch, Mobile Iron, etc..) or just use iPhone Configuration utility or Apple Configurator - you can re-ask this to nail down your particular deployment scenario and we can dive deeper into what you seek to accomplish.