(Resolved) OneDrive cannot Backup PST Files

You will learn why Onedrive cannot backup PST files and how to backup or exclude PST files step by step. The easiest way is to use powerful backup software - AOMEI Backupper.


By Ivy Updated on February 24, 2023

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Can't Backup Outlook PST in the Documents Folder

“I am unable to back up my documents to onedrive and get an error message, 'We cannot back up *.pst in the documents folder. To continue move this file outside an important folder and try again.'

So ...

(1) do I move entire Outlook folder; If so, do I lose all my emails etc.

(2) Can I redirect my email a/cs to the new folder without loss of any date/emails? I use Outlook 365 on pop3 on my laptop (with IMAP on my tablet/android phone).” 

OneDrive Cannot Backup PST

You can not backup Outlook PST files to OneDrive if it is currently in use and Microsoft does not recommend you use OneDrive as a backup solution for PST files. Thus, you can choose to move only the PST files and point Outlook to a new location. And you will not lose the email you have downloaded.

Why can't OneDrive Backup PST Files?

OneDrive offers a huge amount of storage space as long as you subscribe to their plan. Thus, many users want to backup PST files to OneDrive to alleviate the mailbox space issue, but Microsoft says “OneDrive will not backup PST files”. Here are some possible reasons for this suggestion:

  • First, the PST file size is often large. It may contain gigabytes of email stored in a non-structured text database, and the transfer speed is usually slow.
  • Second, the file locking issue. If you have a strong rely on PST files and need to use them in Outlook all day, these files will always be open and locked. And the backup process is also prevented.
  • Third, PST files corruption risk. OneDrive will continuously try to upload the PST files and use a lot of network bandwidth, which may likely result in an incomplete or otherwise corrupted copy.

How to Backup Outlook PST Files to OneDrive

The “OneDrive cannot backup archive.pst” problem means you can't backup the PST file you are using. Just close Outlook and backup PST files. This sounds easy but it’s quite difficult for users who need to use Outlook all day long. The Way 2 below is here to help you with precisely this problem.  

Way 1: Backup PST Files to OneDrive Manually

Here you will use “copy and paste” to move PST files from Outlook Files folder. It requires you to close the Outlook desktop client and before that you need to be sure the PST file location.

To check Outlook Files folder location in Outlook 2010, follow the steps below:

  • Click the File tab and Info > Account settings and select Account settings.

Account Settings

  • Switch to the Data Files tab, click the file containing PST files, and then Open File Location to locate it.

Outlook PST File Location

Then, copy the file location to a paste board and start to backup PST files to OneDrive.

Step 1. Close the Outlook app. Open File Explorer and paste the Outlook Files folder location to access it.

Copy Outlook PST Files

Step 2. Copy the PST file you want to backup and paste it to the local OneDrive folder.

Way 2: Backup PST to OneDrive Automatically

If you want to run this backup task automatically without locking issue, you could consider using powerful backup software - AOMEI Backupper Professional.

It offers you 4 schedule backup options and allows you to backup PST files at off-peak hours or any time you don’t use Outlook with its “Wake the computer to run scheduled backup task” feature.
By default, in a scheduled task, this software will enable “Incremental Backup (default)” to backup only changed files. You can also use “Differential Backup” and automatic backup cleanup methods to save much disk space.
Besides, it allows you to split the backup image to smaller or a specific size automatically to backup large PST files faster.

Please download this powerful backup software to have a try!

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(PS: Windows 11, 10, 8, 7, XP and Vista are supported on the Professional edition. For server users, try AOMEI Backupper Server!)

Step 1. Open Outlook, type email, and click Connect, then follow the on-screen instructions to add the account containing PST files. Then, close it to be sure your files are not locked.

Add Account Oulook

Step 2. Launch AOMEI Backupper Professional and click Backup and Outlook Backup.

Outlook Backup

Step 3. Click Add Outlook data and select the Outlook account containing PST files you want to backup. Then click OK.

Add Outlook Data

Step 4. Click Select a cloud drive and then OneDrive to receive PST files in Outlook.

Select OneDrive

Step 5. Enable “Daily”, “Weekly” or “Monthly” schedule backup and set off-peak hours to backup. Check “Wake the computer to run scheduled task”  to be sure it will always be executed. Click Start Backup to backup PST files to OneDrive automatically without locking issues.

Schedule Backup


  • The Event triggers feature does not support the “Wake the computer to run scheduled task” feature. It only allows you to backup PST files at system startup, or user logon.
  • By default, the Splitting feature will be enabled automatically. To split the backup image into a specific size, go to Options and select Splitting > Custom size.

How to Exclude PST Files from OneDrive Backup

If you cannot backup PST file to OneDrive, you still can choose to remove PST files from OneDrive to ensure that the rest of your data will be safely backed up.

Step 1. Close Outlook. Browse to the Outlook Files folder location, and copy the PST files from the OneDrive folder to a new location outside OneDrive. Rename it for clear distinguish.

Step 2. Restart Outlook and select File > Account Settings (twice). Then, switch to the Email tab and select the account name, and Change Folder.

Change Folder

Step 3. Select the account again and New Outlook Data File... to browse your newly renamed copy .pst files. Click OK to back to the Account Setting window.

Step 4. Switch to the Data Files tab and select the data file location including OneDrive. Click Remove to exclude PST files from OneDrive backup.

 Exclude PST Files from OneDrive Backup


  • The Remove option just disconnects email data from your Outlook account. You just add it back later.
  • You need to set another data file as default before removing the Default data file.
  • If you want to delete the .pst files in OneDrive, you need to close Outlook first.


This article introduces you to 3 possible reasons of OneDrive cannot backup PST files and how to backup or remove PST files step by step. To backup PST files to OneDrive without file locking issues, the easiest way is to use powerful backup software - AOMEI Backupper Professional to help you.

Besides, it is still disk cloning software for Windows 11, 10, 8, 7, etc. So you can use it to clone Samsung 870 EVO SSD, clone NVMe SSD to NVMe SSD, clone PCIe SSD, etc, even OS only. 

Ivy · Editor
Ivy is an editor of AOMEI Technology, she covers backup & restore,hard disk & partitions management and cloud files transfer and so on for AOMEI. She is an outgoing girl and enjoys helping people find solutions to their problems. She loves traveling, eating, reading and so on. She usually hangs out with friends at her leisure time.