I have had a few instances where customers have blocked OneDrive in their Office 365 tenant. This is often the result of a looming Exchange 2010 support deadline and a lack of time to establish governance, security, compliance, and training around both Exchange and every other service in Office 365. Unfortunately, the methods used to block some of these services may have unexpected consequences.
In each of these instances, OneDrive was blocked by removing the user’s ability to create OneDrive storage in the tenant. SharePoint Online was also in its default out-of-the-box state with default permissions. In each case we ran into the following symptoms:
- Despite the OneDrive block, an Outlook Web App user could successfully select the option Save to OneDrive for their attachments
- The attachment would not save to OneDrive, but instead, the default SharePoint document library inside a folder named Attachments
In the next sections, we show how the OneDrive block was put in place and how SharePoint was configured to cause this perfect storm of incorrect attachment saving. We will then identify a workaround for the issue.
How OneDrive was blocked
The method described in this section is commonly found on the internet to block OneDrive access for users. In all cases, OneDrive was configured using this method.
The block is configured by navigating to the SharePoint Admin Center and selecting More Features. From the More Features window, click the Open button under the User Profiles section.

From the User Profiles screen, select Manage User Permissions. On the Permissions for User Profile dialog, select Everyone except external users. In the Permissions box, Create Personal Site was unchecked. When unchecked this removes the user’s ability to create a personal OneDrive site.

Note: This method does not affect users with existing OneDrive storage. To revoke access to existing storage, the site collection admin for each OneDrive personal store would need to be replaced.
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