Limitations for Clumio’s Microsoft 365 backup service

Clumio’s Microsoft 365 backup service currently has a few known limitations.

The Exchange Online backup service has the following limitations:

  1. Emails cannot be exported from the service.
  2. The Last Modified Date Time value for restored emails sometimes do not match the original email.
  3. Encrypted emails without attachments are backed up successfully. However, on restore, they present the following message in their email:
    "This message is protected with Microsoft Information Protection. You can open it using Microsoft Outlook, available for iOS, Android, Windows, and Mac OS. Get Outlook for your device here: With Microsoft Information Protection, you can prevent your email messages from being copied or forwarded without your permission. Learn more at
  4. There may sometimes be a discrepancy between the number of emails in a folder inside a backup on Clumio and the actual emails in Exchange. This occurs very rarely.

The Contacts and Calendars backup service under the exchange has the following limitations: 

  1. Any contacts folders created using the macOS client cannot be backed up.

  2. Contacts marked with categories are restored under a new category.

  3. Contacts marked as favorites are not restored as favorites.

  4. Contacts that have emails such as:

    • home email
    • work email
    • fax email .. etc

    When restored from a backup will be restored as 'other' emails.

  5. In the case of a read-only Calendar restore, a new calendar <unicode_calendar_name> restore <current_timestamp> name is created and the event is restored within it.

The OneDrive Backup Service has the following limitations:

  1. Documents cannot be exported from the service.
  2. Only versions of the file taken during backup are available for restores. Versions between backups cannot be restored.
  3. Link-based permissions are not backed up as and when they are modified. This is a limitation of the Microsoft APIs.
  4. Clumio can only restore direct access permissions.
  5. Redirected permissions restore or Cross domain permissions restore will not give access to a user if that user belongs to another domain.

The SharePoint Backup Service has the following limitations:

  1. Groups for Permissions cannot be restored if the number of groups cross 1000 as Microsoft limits number of groups to 1000.
  2. WebPart pages are backed up successfully, but are restored as folders.
  3. Clumio cannot perform backups of a page until it is published. If a user creates a new page, and a webpage opens where the user can add/edit details. If the user clicks outside the box, the page is saved as a draft. Such drafts are not backed up.
  4. The following content types are unsupported
    • OneNote
    • NewsFeed

Clumio actively works to resolve product limitations as far as possible. This document is updated as issues are resolved.