Microsoft Pauses Exchange Security Update Over Transport Rule Failures

Microsoft has paused the roll out of a security update that was released for Exchange Server 2016 and Exchange Server 2019 on November 12. The company has warned that the patch could break transport rules for select customers.

“We are aware of customers having an issue with the Transport rules stopping periodically after this update is installed. Based on our initial investigation, this can happen to customers who use their own transport or DLP rules. If you are seeing this problem, you might have to uninstall the November SU until it is re-released,” Microsoft explained.

In Microsoft Exchange, transport rules (also known as mail flow rules) help manage the flow of email messages within an organization. They enable administrators to apply specific actions to messages based on predefined conditions. These rules also allow organizations to automate workflows and filter out unwanted content like spam and phishing attempts.

DLP (Data Loss Prevention) rules are designed to protect sensitive information by setting specific conditions and actions within a DLP policy. These rules detect and monitor sensitive data, enforce policies to prevent unauthorized access as well as take preventive actions like blocking or encrypting data.

Admins report transport rule failures after Exchange security update

Several administrators reported on Reddit that their transport rules stopped functioning after installing the Exchange security update. Some users confirmed that restarting the service temporarily fixed the issue, though the problem kept coming back. Microsoft advises affected users to uninstall the update and wait for a new version.

Microsoft engineers are actively working on a permanent fix for the issue. Meanwhile, the company has paused the rollout of the latest Exchange security update. Customers who don’t rely on transport or DLP rules and haven’t encountered any problems can safely install the November 2024 update.