@Learner,Thanks for posting in Q&A.
From your description, I know you are looking for a way to stop Intune Shared Device Policy from deleting data.
Based on my research, the start delete threshold setting means account manager begins deleting cached accounts as soon as total disk/storage space drops below your configured threshold. It will continuously delete to reclaim disk space and stop delete threshold setting means account manager stops deleting cached accounts as soon as total disk/storage space meets your configured threshold and the Inactive account threshold setting means the number of consecutive days after which an account that has not signed in is deleted. Moreover, accounts that have been inactive the longest are deleted first.
Therefore, if you want to stop Intune Shared Device Policy from deleting data, it is suggested that you set Account management Disabled, then it will not auto delete account data.
And if you want to keep user data taking up disk space in a specific interval, you can set Account Deletion as At storage space threshold and set the values of Start delete threshold and Stop delete threshold.
Hope it will help, if there is any update, feel free to let me know.
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