[UPDATED January 2026] This post is a running list of questions I’ve received since 2020 on Purview Retention Policies (NOT Retention labels) in SharePoint and OneDrive and my answers.
Note: My answers apply to both SharePoint and OneDrive sites equally although in my answers I just say “SharePoint”. Also, when I say SharePoint, I mean any type of SharePoint site: Communication site, Group-backed Team site, non-group-backed Team site, Classic site. The only exception is subsite which I explicitly call out in several questions.
Microsoft documentation: Automatically retain or delete content with a retention policy
The questions in no particular order, just as they were asked of me…
Q1: What content is retained by a Retention policy on a SharePoint site?
Answer: documents (all file types) from all libraries on the site, including files in the site assetslibrary. In my experience, although pages in the site pages library will be included for a retention policy that has a “retain” component on it, any “delete” action will not be taken. This means changes to pages will be retained in the Preservation Hold Library for the retention period.
Only files are retained, not folders or libraries. The “before copies” of file changes and files that are deleted are stored at the root of a special system library on the site called the Preservation Hold Library (PHL) for the retention period.
To make file names unique in the library, a GUID is appended to each file name.
Q2: When a retention policy is applied to a site and content is deleted on the site by an end-user before the retention period has been reached, does it go into the recycle bin?
Answer: Yes. The end-user is allowed to delete content – it will automatically go into the SharePoint site’s first-stage recycle bin as normal and will follow Recycle bin processing from that point. However, due to the retention policy applied to the site, a copy of the deleted content will also go into the Preservation Hold Library on the site for the duration of the retention period.
Q3: Does an end-user know that a retention policy has been applied to the site?
Answer: Usually no, but there are a few exceptions.
#1 – if you attempt to delete a folder that has content in it, you will see this message:
#2 – if you attempt to delete a library on the site, you will receive the error messages below:
Q4: When does content retained in the Preservation Hold Library (PHL) get deleted?
Answer: The timing is controlled by a back-end Purview timer job whose schedule you have no insight into. If the retention period has elapsed for an item in the PHL, it is automatically moved to the second-stage recycle bin (not visible to anyone but a site collection admin) where it will be permanently deleted after 93 days.
Q5: If a Retention Policy has been configured to retain and ‘Do Nothing’, what happens to content in the PHL after the retention period?
Answer: The back-end Purview timer job will delete the content out of the PHL during its clean-up process. Other content on the site will no longer be under retention control. (It can be manually deleted if desired)
Q6: Can I see the Preservation Hold Library in Site Contents in a site?
Answer: No. A site collection administrator will not be able to see the PHL in Site Contents on a site; however, they do have permission to the library and so can navigate directly to it at the URL below:
- PHL on a site: ~/sites/<sitename>/preservationholdlibrary
- PHL on a subsite: ~/sites/<sitename>/<subsitename>/preservationholdlibrary
Q7: What is the best way to find content that is being retained by a Retention policy?
Answer: Purview Content Search and eDiscovery search are the administrative tools to help you verify what’s being retained as it includes content from the PHL. This is used to satisfy any regulatory requests/legal holds/legal searches your organization may have.
Q8: Will Microsoft search return results from the Preservation Hold library?
Answer: No. Even though a site collection administrator has access to the PHL and can navigate directly to it, its content will not be returned in a search from the Microsoft search bar. You must use one of the administrative search options (previous question) to see results from the PHL.
Q9: Can I use the Preservation Hold library as a backup for my site?
Answer: No. This is not a point-in-time snapshot of a site’s content. It is capturing all changes and deletions made to content across the site by a retention policy set to retain.
Note: the PHL contains other content as well. See next question and answer for more information.
Q10: Does space consumed by the Preservation Hold library count toward my Site Collection storage quota?
Answer: Yes. The PHL space is included in the storage consumed by the Site Collection it’s in. This is something you must take into consideration for site planning as long-duration retention policies (common) can consume a significant amount of storage over time.
Note: in addition to a retention policy applied to a SharePoint or OneDrive site, there are several other Purview features that also use the Preservation Hold library for preserving content:
- eDiscovery hold targeting a SharePoint or OneDrive site
- Auto-apply label to cloud attachments
- Record retention label applied to content on a SharePoint or OneDrive site
- Tenant level setting allowing users to delete labeled content
- Deleted content from an Elevated risk user (Adaptive protection feature of Insider Risk Management)
All of these features must be planned for and taken into consideration as part of your long-term retention and site architecture strategy due to this PHL dependency.
Q11: Can a retention policy be applied to one subsite?
Answer: No. Retention policies are applied to SharePoint sites (the parent site collection). You cannot apply it to a specific subsite within. (another reason not to use subsites)
Q12: Will a retention policy apply to the subsites I may have under my parent site (collection)?
Answer: Yes. If a retention policy is applied to a site, it will automatically also apply to any subsites that may be under the parent site. In that scenario, a separate PHL will be automatically created in each subsite. The downside of subsites from a retention perspective is they are included in the overall site collection storage quota, including the PHLs across all subsites.
Q13: Can I know in advance when content will be deleted if a Retention Policy is applied to it?
Answer: No. (Other than knowing the settings of the retention policy and looking at either the created date or last modified date of the content on the site, but that is a manual check)
Q14: Can I automatically review content that has a retention policy applied to it before it is deleted (so I can potentially change my mind about deleting it)?
Answer: No. A Disposition Review is only allowed on content that is being retained with a Retention label. A retention policy that automatically deletes content at the end of the retention period is indiscriminate… it applies to all content in the site (refer to Q1 answer).
Content deleted via a Retention policy will automatically go to the second-stage recycle bin on the site for 93 days and will then be permanently deleted.
Q15: Can I have a Retention label and a Retention Policy published to the same location?
Answer: Yes. If an item in the location has a retention label applied to it and a retention policy is also applied to the same location (site), the principles of retention are enforced (image). These principles determine how long an item is retained for and at what point it can be deleted. There is no way to circumvent these principles EXCEPT if there’s an eDiscovery hold on the same location. If that is the case, all deletion activities from either a retention policy or label are halted until the hold is released.
- Link: Principles of Retention and what takes precedence
- Microsoft’s flowchart to validate your retention setup: Retention flowchart
Q16: When a Retention Policy is published to Microsoft Teams channel messages, does it apply to all standard, private, and shared channel messages for the Team?
Answer: Yes. When you publish a retention policy to Teams channel messages, all standard, shared and private channels’ messages under the same parent team will inherit the retention policy settings.
Note: this is a change in behaviour for private channel messages.
Migration of private channel messages in 2025.
Q17: When a Retention Policy is published to a Microsoft Teams SharePoint site, does it apply to standard, private, and shared channel files within the Team?
Answer: No. You need to specify multiple SharePoint sites (each for the channel it relates to) for the retention policy:
- The main SharePoint site backing the Microsoft Teams to include all standard channel content stored in SharePoint.
- The SharePoint site URL for EACH private channel’s site collection to include each private channel’s content stored in SharePoint.
- The SharePoint site URL for EACH shared channel’s site collection to include each shared channel’s content stored in SharePoint.
Q18: Is there any way to delete content on a site that is under retention due to a Retention Policy?
Answer: Yes. In Public Preview (as of January 2026), there is a secure workflow feature called Priority cleanup that will allow you to bypass retention policies (and legal holds) in SharePoint, OneDrive (and Exchange) to allow permanent deletion of content from SharePoint and OneDrive before the retention (or hold) duration expires. There are multiple levels of policy approvals, specific roles assigned, and auditing activities logged.
It’s important to know that this feature will supersede the principles of retention!!
Links:
- Priority cleanup for Exchange: Expedite deletions from mailboxes
- Priority cleanup for SharePoint/OneDrive: Override holds for files in SharePoint/OneDrive
Q19: What is the impact of a retention policy applied to a site and the version history settings? Will the versions still expire based on the version history settings?
Answer: No. A retention policy (with a retain configuration) applied to a site will always override any version history limits you may have in place for libraries on the site. Until the retention period has been met, no versions will be deleted which may result in more versions being retained than your configured limit.
The versioning limit for the document library is ignored. This exemption continues until the retention period of the document is reached (based on the retention policy period). The trim job (Purview timer job that trims existing versions in a library) will stamp an expiration date on the version instead of deleting it if it is subject to a retention policy. Once the expiration date is reached, if the retention policy is still in effect for the version, the expiration date is extended; otherwise, the version is deleted.
Note: an eDiscovery hold will also ignore the version history limits while the hold is in effect on the site.
Link: Version storage behavior
Thanks for reading. 🙂
-JCK