Microsoft is currently rolling out a change that suddenly puts certain users into read-only mode in OneDrive and SharePoint Online, without displaying a clear error message.
If you don’t check now whether your tenant has been affected, your helpdesk will be dealing with unexplained complaints over the coming weeks. Here’s what you need to know and do.
What’s changing?
SharePoint Online has always had storage quotas per user, but enforcement has not always been consistent. Under certain circumstances, the quota assessment during a refresh cycle could fail, resulting in some users being allocated more storage space than their licence permits.
Microsoft is now addressing this issue with Message Centre notification MC1310684. From the end of May 2026, with completion expected in June 2026, all user quotas will be reassessed based on the licence title. Anyone who has exceeded their storage limit will be placed in read-only mode. This means that users will still be able to view files, but will no longer be able to save, create or edit them until the situation has been rectified.
Three scenarios where things could go wrong
For most commercial tenants with standard licence settings, this will have no impact. However, there are two situations in which you could run into problems:
EDU users with an A1 licence
Office 365 A1 entitles users to 100 GB of OneDrive storage. Accounts created for compliance purposes were sometimes allocated 1 TB or more. These are now being reduced to 100 GB.
Users left behind without a licence
OneDrive accounts that are retained after an employee leaves the company but whose licence has been revoked have an expected quota of 0. Any data still stored on the account is technically ‘over quota’.
How do you identify affected users?
Microsoft has published an official PnP script designed specifically for this scenario. You can access it directly via the link in MC1310684:
Identify OneDrive Users Over License-Based Storage Quota (PnP Samples)
The script works exclusively via Microsoft Graph. You do not need SharePoint Online Management Shell or PnP PowerShell. The required modules are installed automatically using the -InstallPrerequisites parameter. The script is entirely read-only: it does not make any changes to your tenant.
There are three scan modes:
- FastScan (default): retrieves all OneDrive data via the Graph Reports API in a single bulk download. Works incredibly quickly, even on large tenants. Drawback: report data is up to 48 hours old. Does not work if your tenant has enabled "anonymous usernames in reports".
- LegacyScan (-LegacyScan): real-time data, but slow for large tenants (expect it to take two hours or more for 10,000+ users). Use this if FastScan does not work due to the anonymisation setting.
- TargetedUser (-UserPrincipalName): check one or more specific users directly. Useful for quickly verifying a report from the helpdesk.
A basic run looks like this:
.\Get-ODBOverQuotaUsers.ps1 -ExportPath "C:\Reports\OneDriveQuotaReport.csv"
The CSV report lists users exceeding their quotas at the top, with columns showing licence tier, expected quota, storage used and how much the user has exceeded their limit. This makes it easy to filter the data in Excel and prioritise follow-up actions.
Is anonymisation disabled in reports?
Check your settings in the SharePoint admin centre under Reports > Settings > Show anonymised usernames in reports. If this is enabled, FastScan will not work and you will need to use LegacyScan or temporarily disable the setting.
What do you do about users who have exceeded their quota?
There are two corrective paths:
- Upgrade the licence. If the user genuinely needs that extra storage, assigning a higher licence tier is the most sustainable solution.
- Reduce storage usage. Work with the user to delete or archive files until the licence limit is reached.
For abandoned users without a licence, the right choice depends on your organisation’s retention policy. Options include: assigning a minimal licence to the account, archiving the content externally, or accepting that the account will remain in read-only mode until it is deleted.
What if all your users are within their licence limits?
In that case, you don’t need to do anything. Microsoft does not adjust quotas, delete files or send notifications to users who remain within their limits. The change only affects accounts that have already exceeded their licence-based limit.
Nevertheless, it’s worth running the PnP script at least once, if only to establish a baseline. Storage usage is gradually increasing, and if you know where you stand today, you can make proactive adjustments later on.
