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Backup and restore

This section covers the key semantics and related concepts for backup and restore actions in Alcion.


Resources in Alcion are the primary Microsoft 365 organizational units on which backups operate. They are related, but not directly equivalent, to the set of supported services. Below is a summary of the supported resource types and the services and data types they map to:

  • User - Exchange mailbox and OneDrive data for a licensed Microsoft 365 user or Exchange shared mailbox with an associated OneDrive1. to a shared mailbox where the previous OneDrive still exists.
  • Site - Sharepoint document libraries, pages, and lists for a SharePoint site.
  • Team or Group2 - Public and private channel messages, Sharepoint sites, and Group mailbox for a Microsoft Team or Group.
  • Shared mailboxes - Exchange shared mailbox without an associated OneDrive.


The initial backup for any resource is a full backup. All subsequent backups capture, and potentially transfer, only data that has changed since the previous backup. While the data is captured incrementally, Alcion materializes each backup as a full synthetic backup which has a listing of all items stored in Microsoft 365. This means there’s no “chaining” between backups and restoring an item from a backup requires only accessing information contained in or referenced directly in a single backup. This makes backups independent from each other once they’ve been created and results in an efficient restore experience.

Alcion supports two methods for initiating backups:

  • On-demand - Administrators initiate backups on resources explicitly at their discretion.
  • Recurring - Alcion automatically initiates backups according to a backup policy that administrators configure for resources.

Backup policies determine how Alcion manages the scheduling of backup scheduling for resources where a backup policy is set. The available policies vary based on your subscription plan. They range from traditional recurring backups using a predefined schedule to AI-driven intelligent backups that optimize the backup schedule for you.

Finally, Alcion retains backups based on a robust retention policy.


Alcion can restore individual items or collections of items from a previous backup for a given resource. Administrators can browse specific backups based on a desired recovery point-in-time or can search for items across all backups. Once the desired items are identified, the administrator can initiate a restore.

Restore options

Alcion supports the following options to control the behavior of restores:

  • Restore to a different location (default) By default, Alcion performs non-destructive restores to a dedicated Alcion_Restore_<Timestamp> folder which preserves the original hierarchy of the recovered items. This guarantees that no existing data will be overwritten as part of the restore operation.

  • Restore to original location Additionally, Alcion allows restoring data to the original location at the time of backup. In this case, it's possible that some items restored already exist, and one can control the behavior when this happens as follows:

    • Skip (default) - Alcion won't restore items that already exist.

    • Keep as copy - Alcion will restore the item as an additional copy with a modified name (for example my file (1).docx).

    • Overwrite - Alcion will replace the live item with a copy from backup. This option can lead to data loss and should be exercised with care.


      Handling of existing items, as described above, happens at the level of individual items in a folder and not the overall folder level. Alcion will re-create folders if they no longer exist, but won't create a copy of a folder or overwrite a folder if it exists in the live data.

  • Restore to a different resource Lastly, Alcion also offers the ability to restore to a new resource (for example, user or site). The resource needs to already exist and have the proper Microsoft 365 license. The data will be restored to a dedicated Alcion_Restore_<Timestamp> folder at the root of the resource.

  1. A Shared mailbox can have a OneDrive library if it was previously a licensed user converted to a shared mailbox, or if it's a shared mailbox with an assigned Microsoft 365 license.
  2. Resource type that's in active development or in Private Preview.