We've got an issue where a user assigns tasks to users and has set up a custom category for each user, but once the user updates the tasks, the return messages remove the category. It seems changing the Transport Config rule to set -ClearCategories = False would fix this, but I would like to know what the implications are and why this is the default in the first place. Thanks Dan

Hi, You can change the value of ClearCategories to false. It will not cause the potential issues. If the some users want to clear categories when receiving a task update, they can use a outlook rule to archive it. Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT