As communicated in MC256835 (May ’21), starting August 16th 2021 the service will retain 30 days worth of versions for any PST files stored OneDrive for Business and SharePoint Online team site document libraries. This change will prevent cases of previous versions of PST files quickly consuming available storage. The change will only impact previous versions of PST files stored in your document library storage. This feature is associated with Microsoft 365 Feature ID: 72237.
This update will help customers manage PST file versions from consuming storage capacity for OneDrive & SharePoint Online. PST files are a type of Outlook Data File which can consume a lot of storage – especially when versions are considered. The service will now limit the number of PST versions retained, often resulting in less storage consumption.
- SharePoint Online
- OneDrive for Business
As best practice PST files should not be uploaded on OneDrive for Business and SharePoint Online team site document libraries due to the impact on storage and network bandwidth. When PST files are uploaded on OneDrive for Business and SharePoint Online team site document libraries, Outlook updates PST files generating multiple versions which leads to storage being quickly consumed by the multiple versions of the PST file.
The SharePoint Online Management Shell cmdlet Set-SPOTenant – DisableOutlookPSTVersionTrimming $true can be used to opt out until August 13th 2021. This will have no effect after the deadline. Opt out only applies to existing document libraries and does not apply to new doclib created after August 13th 2021. New behavior will be automatically enabled if you don’t opt out by deadline.
- Command: Get-SPOTenant/Set-SPOTenant
- Parameter: DisableOutlookPSTVersionTrimming
- True – Opt-out to the versioning change
- False – default value
How this will affect your organization
As part of the change, version history for PST files will be retained for up to 30 days. Document libraries will be updated with new PST version retention limits. Once this change is rolled out to your tenant, versions of PST files stored on in your document library that are older than 30 days will be permanently deleted. With these changes the service will always retain a minimum of 30 day worth of PST versions that can be restored from.
What you need to do to prepare
No action required – Document libraries will be updated with new PST version retention limits. If you wish to opt out of the PST version retention update, you will need to execute the SharePoint Online Management Shell cmdlet provided in this post by August 13th 2021.
To prevent uploading .PST files from the OneDrive sync app, read Block syncing of specific file types and To move .PST files out of OneDrive, read How to remove an Outlook .pst data file from OneDrive.
Message ID: MC277809
Published: 13 August 2021
Updated: 13 August 2021
Effective: August 13, 2021