SharePoint Expiring Access Policy Controls Sharing Links Issued to Guests
In the summer, Microsoft introduced an expiring access policy for external users in SharePoint Online sites and OneDrive for Business accounts. In a nutshell, a tenant can set a policy to control the number of days a sharing link lasts after a user shares some content with an Azure AD guest account (created automatically when sharing with an external user). The expiring access policy doesn’t apply to guest accounts who access content through their membership of Microsoft 365 groups (teams). Their ability to work with content in SharePoint Online is controlled by the guest’s membership instead of a sharing link.
By default, the expiring access policy is not set. A tenant or SharePoint administrator must enable it and define the sharing period in the Sharing section of the SharePoint Online admin center (Figure 1). The period can be from 30 to 730 days.

Once set, the policy applies to new sharing links. It also applies retrospectively to old links. The policy defined in the SharePoint Online admin center applies to all SharePoint sites and OneDrive for Business accounts. You can override the expiration period on a per-site basis.
Unlike other expiration policies used in Microsoft 365, like the Teams meeting recording auto-expiration policy or even retention policies and labels, content remains unaffected when an expiration period lapses. The only effect is on the sharing link which becomes invalid and unusable for access.
What Happens When Sharing Links Expire
As sharing links approach expiration, users receive warnings through two means. First, a banner appears in OneDrive for Business (Figure 2). The text could be better as it’s a sharing link which expires rather than a user. The Azure AD guest account will remain and can be used for other purposes, such as other sharing links or as a member of a group or team. The logic here might be that people manage sharing access on a user-by-user basis, so it’s appropriate to refer to users expiring.

The second method is email. SharePoint sends a note to people to advise them when sharing links are within ten days of expiration (Figure 3). In both cases, the Manage (or Manage access) link allows the user to update the soon-to-expire sharing links.

Clicking the link brings up the Access Expiration fly-out pane (Figure 4), which lists all sharing links created by the user subject to the expiring access policy. As you can see, some of the links are quite a long way off because the tenant has a 120-day expiration policy.

To extend the validity of a sharing link, select a user and click Yes, extend (Figure 5). SharePoint Online will then extend the sharing link by the maximum period allowed, in this case 120 days from the current date. You can also remove a sharing link if it’s no longer needed.

Good Practice to Implement Expiring Access Policy
It’s good practice and makes good sense for Microsoft 365 tenants to implement an expiring access policy. Many expiring sharing links will need no intervention by content owners when they expire. Other links will need an extension, which is a quick and low friction action. Overall, there’s nothing much to dislike about implementing an expiring access policy where links expire after a reasonable period, like 90 to 120 days. Organizations which store more sensitive content in SharePoint could reduce the expiration period and couple expiration with the targeted availability to content available with sensitivity labels.
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Regarding the message: “Review users who will lose access to [Tony Redmond] soon.”
What kind of resource is [Tony Redmond]? Is it the name of a shared file, a folder or the SPO/ODfB site name?
It’s a quirky kind of text. In this instance, I believe it’s “lose access to content shared by Tony Redmond.” At least, that would make more sense.
Is it possible to send reminder mail to Site Owner ?
I don’t believe so. You might be able to scan the Office 365 audit log for sharing link creation events and use that to generate email to site owners to remind them that links will expire.
Invited users recieve reminder of the expiration? or only who create the links?
If not, is there any way to do it?
Thanks!
Site administrators get the reminder. Users don’t. It’s up to the administrators to take action.
Can I set the expiry time per site? I want one site to have no expiry date and another expire in 30 days.
Covered in the article. The answer is that you can set specific expiry periods on a site basis.
I have an ongoing support tickeet with the PG at Microsoft about this feature, because the “expiring access” emails are being sent to group members and even the guests themselves in the past few months!
This specific bug (bug, in my opinion) occurs on sharepoint sites linked to O365 groups/teams. and in these cases, the emails send not only to owners, but to ALL members of the group (ergo site). am i alone?