What happens to the auto-delete setting when the user of the inactive device is assigned to a different profile?

The auto-delete setting of the changed profile becomes applicable. If auto-delete is not configured in the changed profile, device just remains in the inactive state until it reconnects to inSync Server. 

What happens to the inactive device when the device user is assigned to a new profile already configured with auto-deletion for which the device has already crossed the delete date?

inSync runs a daily check to identify devices scheduled for auto-delete. If a device user is assigned with a new profile because of which the device has already crossed the delete date, inSync deletes the device when it performs the next check. 

What happens to the device of the preserved user when the user is activated?

When a preserved user is activated, inSync ensures that the devices attached to the user get connected to inSync Server. This resets the last server connection time of the device to the user activation date. Thus, even if the profile assigned to the user has auto-deletion configured in it, the device does not have the risk of getting auto-deleted.

Does auto-delete setting  also delete devices on Legal Hold and disabled devices?

No. Auto-delete setting does not delete devices on Legal Hold and disabled devices.

What is the relation between User Backup Inactivity Alert and auto-delete inactive device setting?

The User Backup Inactivity alert is raised when a device has not backed up for a specified number of days. A device is marked inactive when it has failed to connect to inSync server for a specified number of days.

The auto-delete inactive device setting deletes only the inactive devices and has no relation with the User Backup Inactivity alert.

Where can I see all the inactive devices and the date when they will get deleted?

You can run the Inactive Devices Report to view all the inactive devices in inSync. If the profile associated with the device is configured with auto-delete inactive device setting, the report displays the date on which the device will get deleted.

Will all the inactive devices get auto-deleted?

inSync does not delete all inactive devices. If the device user is assigned with a profile that is configured with auto-delete setting, only then the inactive device will get deleted after the specified interval.

What will happen to the user data once the device is auto-deleted?

Backup data of a device already deleted by auto-delete inactive device setting cannot be recovered.

Some of my devices are in inactive state as they were not getting backed up, based on the earlier definition of inactive device. Since the definition of inactive has changed, will inSync continue to treat these devices as inactive?

All devices, which were marked inactive due to backup inactivity, will be marked as active and the last connected date will be reset to recent. This will be a one-time activity. If the device continues to remain disconnected with inSync Server, inSync will mark it inactive based on the setting under Manage Inactive Devices. The device will be scheduled for deletion only if auto-delete is configured in the user’s profile.

When I configure auto-delete of inactive devices, there will be several devices which will get scheduled for deletion. Will inSync delete all the devices together? 

Initially, you may see several devices scheduled for deletion on the same day. inSync will delete devices in groups to avoid overloading the deletion process. If there are large number of devices, inSync may take a longer time to delete the devices. In this case, you may continue to see the devices in the inactive devices report even after the date of deletion, before the device is eventually deleted.

How to calculate the date of auto-deletion? 

inSync allows you specify the number of days after which a device will be marked as inactive in the absence of any connection between the device and inSync server. It also allows you specify the number of days after which inSync must delete inactive devices if they continue to remain inactive.
Let us assume a device was last connected on Jan 1 2018. And the profile is set to mark the device as inactive if not connected for 15 days and auto delete if it continues to stay inactive for 100 days. 
 
Assuming, inSync server is unable to make further connections with the device,
 
The Device will be marked as inactive on =  Jan 1, 2018, + 15 = Jan 16, 2018
The Device will be marked for deletion on = Jan 16, 2018 + 100 days =April 26, 2018

Note:

• For devices with Device trace disabled, inSync will reset  their last connected date on June 10, 2017.
• For Devices with Device trace enabled, inSync will continue to use existing last connected date.

Which devices do not get deleted when auto-delete inactive devices setting is configured?

The auto-delete inactive devices setting excludes the following devices from deletion:

• Disabled devices
• Devices on Legal Hold
• Devices of  preserved users.

If administrator has disabled backup of mobile devices, does it get automatically marked as Inactive if the device has not connected to inSync Server?

No. Mobile devices associated to a profile, which has not allowed backup of mobile devices, is not marked as Inactive.