IRM Enabled SharePoint 2019 Files Opening Unencrypted in Office Online Server but Encrypted When Downloaded

Question

We have configured Information Rights Management (IRM) on our SharePoint 2019 environment and integrated it with an autonomous IRM setup. However, we are facing an issue where IRM-protected documents open unencrypted when viewed in Office Online Server (OOS), while downloading the same files results in properly encrypted files as expected.

Our setup details:

• SharePoint Version: SharePoint 2019
• IRM Integration: Autonomous (standalone) IRM
• Office Online Server: Configured to work with SharePoint 2019

Issue:

• When IRM-protected files are opened in Office Online Server, they appear unencrypted.
• When the same files are downloaded, they are correctly encrypted.

Expected Behavior:

• IRM-protected files should maintain their protection when opened in Office Online Server.

Steps Taken:

1. Verified that IRM is correctly configured in SharePoint 2019.
2. Checked permissions and configurations between SharePoint 2019 and Office Online Server.
3. Ensured that autonomous IRM integration settings align with SharePoint requirements.

Questions:

1. Why are IRM-protected files opening unencrypted in Office Online Server?
2. Is there any additional configuration required for Office Online Server to enforce IRM policies correctly?
3. Are there any known issues or compatibility considerations between SharePoint 2019, OOS, and autonomous IRM integration?

Any insights or suggestions to resolve this issue would be greatly appreciated!

Answer 1

Hi @PratikSavla,

IRM-protected documents cannot be encrypted in Office Online Server and Office Web Apps Server. This is because Office Online Server and Office Web Apps Server rely on the document host system, such as SharePoint, to communicate with Rights Management servers because it has no means to directly communicate with Rights Management servers. IRM protection prevents Office Online Server and Office Web Apps Server from allowing editing of IRM protected documents. Documents that have any IRM permissions modification or protection added from Office applications and are stored on a document management system can't be opened by Office Online Server and Office Web Apps Server. This is true with IRM protected documents that are stored on other third-party host systems. Therefore, IRM-protected files opening unencrypted in Office Online Server is expected behavior.

Reference: Office Online limitations and features with Information Rights Management (IRM).

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