Block synchronization of specific file types (OST files)
![Block synchronization of specific file types (OST files)](https://365tips.be/wp-content/uploads/2020/11/image-212.png?v=1606590690)
You can prevent users from uploading specific file types when they sync their OneDrive files.
OneDrive admin center
Browse to https://admin.o nedrive.com - press Sync, and block the desired file extents in this format:
.ost
.pst
.pkg
.iso
Ost = Outlook ofline folder
PST = Outlook data file
PKG = a mac installation file
iso = an image file for Windows, for example.
![](https://365tips.be/wp-content/uploads/2020/11/image-212-1024x766.png?v=1606590690)
The result!
As a result, OSTs in this case will no longer end up on users' personal OneDrives.
This fixes 2 problems: Long synchronization times due to large files. And prevents forwarding of these files.
This view shows you clearly which types of files are not allowed.
![](https://365tips.be/wp-content/uploads/2020/11/image-209-1024x687.png?v=1606590621)
This view shows where the "problem" file is located.
![](https://365tips.be/wp-content/uploads/2020/11/image-213-1024x775.png?v=1606591090)
![](https://365tips.be/wp-content/uploads/2020/11/image-214-1024x869.png?v=1606591130)
After deleting, you will see that there are no more errors on the OneDrive client.
![](https://365tips.be/wp-content/uploads/2020/11/image-215-1024x843.png?v=1606591170)
Powershell Commandlets: Set-SPOTenantSyncClientRestriction | Docs
Source article: Block syncing of specific file types - OneDrive | Microsoft Docs
Also read this complete OneDrive tips.