Hi,@pavanVC
Thanks for posting your question in the Microsoft Q&A forum.
According to your description, you want to run a calcheck for a office365 users mailbox without a Outlook.
Unfortunately, calcheck cannot be run without Outlook. I suggest you install Outlook and then run calcheck.
If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.