Considerations and Limitations

Considerations and limitations specific for the Veeam Backup for Microsoft Office 365 are listed below.

1. Microsoft Windows Server 2008 operating system is not supported; Microsoft Windows Server 2008 R2 SP1 is minimal supported server OS version.
2. Using FAT32 is not recommended due to database size limited to 4GB; NTFS and ReFS are recommended file systems.
3. Maximum number of mailboxes under protection depends on the mailbox size, the amount of mailbox activity, and Internet connection bandwidth (for slow links) or Microsoft Office 365 API throttling setting (for fast link).
4. Requirements and limitations from Microsoft can be found here: https://products.office.com/en-us/office-system-requirements/#Office365forBEG. In particular, it is impossible to modify throttling policies for Exchange Online. If you need to modify these settings, please contact Microsoft technical support.
5. If you have participated in the public beta of Veeam Backup for Microsoft Office 365, be sure to uninstall the pre-release versions of Veeam Backup for Microsoft Office 365 and Veeam Explorer for Microsoft Exchange, and delete the content of archive repository folder as well as C:\ProgramData\Veeam\Backup365 folder before running the setup.
6. Veeam Backup for Microsoft Office 365 does not support accounts registered in the following Microsoft Azure regions: Azure Germany, Azure China.
7. If you modify the retention policy tag for a folder, Veeam Backup will perform full synchronization of that folder during the next job run. The reason is that any change to retention policy makes changes to all items in the folder (modifies tag, updates last modification time). Such changes are treated by synchronization mechanism as the new item version, which, in turn, automatically initiates a full sync. To read more, see this TechNet article.