OneDrive assigns a cloud storage quota to each account based on the Microsoft 365 license subscribed. Since 2026, Microsoft strictly aligns these quotas with the rights included in each license: an account that exceeds its authorized capacity switches to read-only mode until the user frees up space or the administrator adjusts the quota. Understanding this mechanism is the starting point to avoid any blockage.
Read-only mode on OneDrive: the mechanism to know
Switching to read-only mode means that file synchronization stops. Documents remain accessible for viewing, but any modifications, additions, or file creations are blocked as long as the stored volume remains above the quota.
This tightening particularly affects organizations where custom quotas had been configured well beyond the actual capacity of the license. Administrators who had raised limits to several terabytes without corresponding storage add-ons now see these accounts forced to comply.
To manage OneDrive storage without waiting for a blockage, the first action is to check the quota actually allocated by the active license, directly from the Microsoft 365 admin portal or the OneDrive settings page.
Files on demand and Windows Storage Sense: freeing up local disk space
The Files on Demand feature allows you to view all your OneDrive documents in File Explorer without them taking up space on the local disk. Each file appears with a cloud icon: it is only downloaded when you open it.
The common trap is to open many files without ever switching them back to “online-only” mode. These files then retain a local copy that eats up hard drive space, sometimes several gigabytes on a machine with limited SSD.
Setting up Storage Sense to automate cleanup
Windows Storage Sense (available since version 1809) works in tandem with OneDrive. Once activated, it automatically switches local files that you haven’t used for a configurable period back to “online-only” mode.
- Open Settings, then System, then Storage, and enable Storage Sense.
- In the advanced settings, set the frequency of execution (daily, weekly, or when disk space is low).
- Adjust the delay after which an unused OneDrive file switches back to online-only (30 days is a good compromise for most uses).
- Storage Sense only runs on the C: drive, which requires that the OneDrive folder is located on the system partition.
This combination of Files on Demand and Storage Sense addresses most local disk space issues without affecting the cloud quota.
Recycle Bin and version history: two hidden data reservoirs
Deleting a file from OneDrive does not immediately free up the corresponding space. The file moves to the OneDrive Recycle Bin, which retains deleted items for 93 days. During this entire period, these files continue to count against the quota.
The Recycle Bin has two levels. The first-level Recycle Bin is visible to the user from the OneDrive web interface. The second-level Recycle Bin, accessible only by an administrator or via a specific link in the web interface, stores files deleted from the first Recycle Bin. Both levels consume quota.
Version history: a discreet volume multiplier
Each change saved on a Word, Excel, or PowerPoint document generates an automatically saved previous version. On a 50 MB presentation file modified daily, the history can accumulate hundreds of megabytes in just a few weeks.
To reduce this volume, access the file details in the OneDrive web interface, open the version history, and manually delete outdated versions. It is also possible to limit the number of versions retained at the underlying SharePoint site level if you have administrative rights.
OneDrive “pay-as-you-go” billing: what changes at the end of 2026
Microsoft is preparing a pay-as-you-go billing option for OneDrive storage, with general availability targeted for November 2026. The principle is based on a model where the administrator can raise a user’s limit beyond what their license allows, while only paying for the actual usage above the included quota.
A user with 1 TB included in their license and whose limit is raised to 3 TB incurs additional costs only after exceeding the 1 TB threshold, and only on the actual excess. This option complements existing “Extra Storage” add-ons without replacing them and remains capped at around 25 TB per user.
For organizations where only a few users occasionally exceed their quota (video editors, architects, marketing teams), this model avoids the need to purchase an oversized plan for all licenses. Pay-as-you-go billing specifically targets storage spikes without altering the overall pricing structure.
Selective sync and sorting large folders
Selective sync, distinct from Files on Demand, allows you to choose which OneDrive folders appear in File Explorer. Unchecked folders are neither downloaded nor indexed locally. This approach is suitable for secondary workstations or mobile devices where only a subset of documents is needed.
To identify the largest folders in the cloud, the OneDrive web interface offers sorting by size. Video files, database exports, and old photo backups typically constitute the largest consumption items. Moving these files to external storage or archiving them locally before deleting them from the cloud remains the most direct method to recover quota.
Microsoft’s tightening of quotas makes proactive management of OneDrive storage less optional than before. Regularly checking the Recycle Bin, limiting version history on large files, and monitoring the arrival of the pay-as-you-go model at the end of 2026 are three concrete actions that prevent switching to read-only mode at the worst moment.