OneDrive File Issues

How to Remove Outlook PST Backups from OneDrive and Free Up Storage

Maira Mehtab Sep 28, 2026 870 views

Question details

The user needs to delete Outlook PST files and their generated backup versions from OneDrive to free up available storage space.

Product: Microsoft Outlook and OneDrive
Device & OS: not provided
Scenario: OneDrive is automatically backing up active changes to a PST file, consuming large amounts of cloud storage, and preventing standard deletion.
Observed behavior: The PST file continuously creates historical backup copies whenever modified, taking up excessive space, and the system blocks attempts to delete the files normally.

Before you start

Ensure Microsoft Outlook is completely closed before attempting to delete or move the PST file from OneDrive to prevent file lock errors.

Solution 1Recommended

Disconnect Outlook and Remove the PST File from OneDrive

Safely sever the connection between Outlook and OneDrive to stop continuous syncing, then delete the PST file and its historical versions.

Storing an active Outlook data file (PST) on a cloud or network location like OneDrive is unsupported by Microsoft. It forces OneDrive to continuously upload changes, which creates massive backup versions, quickly consumes your storage limit, and risks severe file corruption.

Close Microsoft Outlook

Make sure the Outlook application is entirely shut down on your computer. If necessary, use Task Manager to verify that no background Outlook processes are running.

Relocate the PST File Locally

Open File Explorer and navigate to your OneDrive folder. Locate your Outlook PST file, cut it, and paste it into a local directory that is not synced by OneDrive (such as C:\Users\[Username]\Documents\Outlook Files).

Delete Historical Versions from OneDrive

Sign into OneDrive on your web browser. Navigate to the location where the PST file was previously stored, check the Recycle bin or use the 'Version history' feature to delete old backup versions and reclaim your storage space.

Reconnect the PST in Outlook

Launch Outlook, go to File > Account Settings > Account Settings, and click the Data Files tab. Add the PST file from its new local directory so you can access your emails normally.

Adjust Backup Settings: Review your OneDrive backup configuration (Settings > Sync and backup > Manage backup) to ensure it is not set to automatically sync your local Outlook data folders.

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Frequently Asked Questions

Why can't I delete my PST file from OneDrive normally?

If Microsoft Outlook is currently open and connected to that PST file, it places a read/write lock on the file. You must completely close Outlook to release this lock before Windows or OneDrive will allow you to delete or move the file.

Is it safe to store an Outlook PST file on OneDrive?

No. Microsoft explicitly advises against storing active PST files in OneDrive or other cloud/network drives. The constant read/write operations conflict with cloud sync mechanisms, leading directly to data corruption and missing emails.

How do I stop OneDrive from creating multiple backup versions of my files?

OneDrive automatically creates a new version every time a file is modified. For files that change constantly (like a PST file), the only way to stop this is to move the file out of your synced OneDrive directory to a local folder on your hard drive.

Document & File Issues