Recently we figured out few issues with our Intune enrollment and apps installation and apps were not getting installed on Intune managed device, After troubleshooting we found Lockdown mode was enabled on the device which was running iOS 16+
As part of iOS 16, Apple introduced a new Lockdown mode. An often state-sponsored hacker is likely to use this feature on a small percentage of high-risk targets.
Lockdown Mode is the first major capability of its kind designed to offer an extreme, optional protection for the very small number of users who face grave, targeted threats to their digital security.
Lockdown Mode includes the following protections:
Messages: Most message attachment types other than images are blocked. Some features, like link previews, are disabled.
Apple services: Incoming invitations and service requests, including FaceTime calls, are blocked if the user has not previously sent the initiator a call or request.
Wired connections with a computer or accessory are blocked when iPhone is locked.
Configuration profiles cannot be installed, and the device cannot enroll into mobile device management (MDM), while Lockdown Mode is turned on.
How to enable Lockdown mode
Turning on Lockdown mode is as simple as heading over to Settings -> Privacy & Security -> Lockdown Mode -> Turn on Lockdown mode
Enable Lockdown mode
Click -> Turn on Lockdown mode
Click -> Turn on & restart
Provide your device passcode
Observations with lockdown mode before and after enrollment enablement
Observation 1: If any user has enabled the Lockdown mode prior to enrollment then Configuration profiles cannot be installed, and the device cannot enroll into mobile device management (MDM) / Intune, while Lockdown Mode is turned on
Observation 2: if any user has enabled the lockdown mode after enrolling to MDM platform, Before Lockdown Mode was activated, all apps that attempted to install successfully were installed, however, once Lockdown Mode was activated, none of the apps could finally be installed.
How to turn off Lockdown mode
Turning Off Lockdown mode is also simple as heading over to Settings -> Privacy & Security -> Lockdown Mode -> Turn off Lockdown mode
Lockdown mode is already On
Click -> Turn Off lockdown mode
Click -> Turn off & restart and following by device passcode