behavior of SharePoint Online site storage notifications.

Question

Behavior of SharePoint Online site storage notifications.

1. Is there any supported way to completely disable SharePoint site storage limit notification emails sent to site owners?
2. What is the exact function of the “Allow notifications” option under Site storage limit in the SharePoint Admin Center?
   • Does this setting only control whether admins can configure a custom notification threshold?
     • Or should disabling it stop all storage-related notification emails?
     1. When “Allow notifications” is unchecked, will SharePoint Online still send system-generated storage warning emails?
     2. What is the default storage usage threshold at which SharePoint Online automatically sends storage limit warning emails if no custom notification threshold is configured?
3. Are these storage limit notification emails considered system-generated (by design) and therefore not configurable or disable‑able by tenant or site administrators?

Answer 1

Hello @Engineer  

I want to gather some information regarding your concern:

1/ Can SharePoint Online storage‑limit notification emails be completely disabled?

SharePoint Online does not offer any supported method to fully disable all storage‑limit notification emails. Microsoft’s documentation only covers how to manage storage (Automatic vs. Manual) and set per‑site limits, but does not provide any option to turn off system‑generated alerts. These emails are part of Microsoft's backend processes, so they continue to be sent even when no custom notifications are configured.

2/ What does Allow notifications actually control?

Allow notifications only controls custom warning emails tied to Manual per‑site storage limits, specifically the emails sent when a site approaches the admin‑defined quota. Microsoft explicitly describes this setting in the context of Manual mode only. It does not affect any system‑generated alerts, so turning it off stops only the custom warnings but not the system’s internal notifications.

3/ If Allow notifications is turned off, will system‑generated storage emails still be sent?

SharePoint will still send system storage alerts. This is because Allow notifications only controls the warnings linked to the manual quota settings, whereas system alerts come from SharePoint’s internal timer jobs (e.g., emails from no‑******@sharepointonline.com). These system‑level processes operate independently and continue sending alerts even if custom notifications are disabled.

4/ What is the default storage‑warning threshold when no custom threshold is configured?

Microsoft does not publish or expose the default alert threshold used in Automatic mode. According to Microsoft Q&A, the “approaching storage limit” threshold in Automatic mode is undocumented, meaning admins cannot view or adjust it. It is fully controlled internally by Microsoft, so there is no way to know whether the system triggers warnings at 90%, 95%, or another value.

For your reference, I will also include a list of relevant articles to help you understand the topic more broadly.

Manage site storage limits in SharePoint in Microsoft 365 - SharePoint in Microsoft 365 | Microsoft Learn 

Manage site storage limits in SharePoint in Microsoft 365 – Westcoast Cloud Help Center 

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations about the quality, safety, or suitability of any software or information found there. Make sure you fully understand the risks before following any suggestions from the link above. This link is in English; Please translate it into your language to follow the guidelines. 

If you still need my assistance, please come back with screenshots or any additional details so I can review it again and see if there’s anything more I can help you with. 

Have a nice day! 

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Answer 2

1. There is no documented, supported way in SharePoint Online to completely disable storage‑limit notification emails that are sent when a site approaches its configured storage limit. The documented controls focus on:
   • Choosing Automatic vs Manual site storage limits at the tenant level.
   • Setting per‑site storage limits and whether notifications are sent when those limits are approached.
2. Function of “Allow notifications” under Site storage limit in the SharePoint admin center: When tenant storage management is set to Manual, admins can set per‑site limits and control whether site admins/owners are notified as the site approaches that limit. From the documented steps for setting individual site limits:
   • Admins select a site → General tab → Storage limit → Edit.
   • They enter a maximum storage in GB.
   • They then “Allow notifications to notify site admins when site approaches storage limit.”
   Based on this:
   • The Allow notifications option controls whether SharePoint sends warning emails to site admins/owners when the site approaches the configured storage limit for that site.
   • It is tied to the per‑site storage limit configuration and the “approaching limit” behavior.
   More specifically for the sub‑questions:
   • It does more than just expose a UI for a threshold; it controls whether those “approaching storage limit” emails are sent when the site nears its configured limit.
   • Disabling it is intended to stop those “approaching storage limit” notification emails that are associated with the configured per‑site limit.
   However, the documentation does not describe any broader effect on other possible system messages; it only states that this setting is used “to notify site admins when site approaches storage limit.” 2.1. When “Allow notifications” is unchecked, the documented behavior is that SharePoint does not send the “site approaches storage limit” notification emails for that site. The documentation does not describe any additional system‑generated storage emails that would continue regardless of this setting. 2.2. The documentation does not state any default storage usage percentage or threshold at which SharePoint sends storage warning emails if no custom notification threshold is configured. It only states that admins can “enter a value as a percent for how full you want the storage to be when the email is sent” when notifications are enabled, without specifying a default.
3. The documentation treats these as built‑in notification behaviors associated with storage limits, but it does not explicitly classify them as “system‑generated and not configurable” in a general sense. What is documented:
   • Tenant admins can choose Automatic or Manual site storage limits.
   • When using manual limits, tenant admins can set per‑site limits and choose whether to allow notifications and at what threshold.
   There is no documented tenant‑wide switch to completely disable all storage‑related notification emails across SharePoint Online, and no additional configuration options beyond the per‑site Allow notifications and threshold when using manual limits.

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References:

• Manage site storage limits in SharePoint in Microsoft 365
• SharePoint storage planning
• Pooled storage management
• SharePoint limits