Microsoft shared a temporary workaround for customers experiencing Outlook freezes after installing this month’s Windows security updates.
As explained one week ago, when Microsoft acknowledged the issue, the bug causes the classic Outlook desktop client to hang for users with POP email accounts who have deployed the KB5074109 security update on Windows 11 25H2 and 24H2 systems.
Other symptoms include the inability to reopen Outlook without ending the process via Task Manager or restarting the device, Outlook redownloading emails, and emails not appearing in the Sent Items folder even though they were sent.
In a Tuesday update, it added on the Windows health dashboard that any app may “become unresponsive or experience unexpected errors when opening files from or saving files to cloud-backed storage, such as OneDrive or Dropbox.”
“For example, in some configurations of Outlook that store PST files on OneDrive, Outlook might become unresponsive and fail to reopen unless its process is terminated in Task Manager, or the system is restarted,” Microsoft explained. “In addition, sent emails might not appear in the Sent Items folder, and previously downloaded might be downloaded again.”
It also said that these problems also affect Windows 10 users and multiple Windows Server platforms, including Windows Server 2025, Windows Server 2022, and Windows Server 2019.
Microsoft’s Windows and Outlook teams are investigating the issues, but the company has yet to provide a timeline for a fix or workaround. However, until a permanent fix is available, Microsoft advised affected customers to access their email accounts via webmail or to move their Outlook PST files out of OneDrive.
Affected users can also work around the issue by uninstalling the KB5074109 or KB5073724 updates. This requires them to open the Settings app, go to Windows Update > Update history > Uninstall updates, and click the “Uninstall” link next to their entry.
However, as Microsoft also warns, removing security updates may leave your Windows devices exposed to malware and other threats, since they patch security vulnerabilities that are often exploited in attacks.
Over the weekend, Microsoft released emergency out-of-band updates for Windows 10, Windows 11, and Windows Server to fix credential prompt failures impacting remote connection applications and preventing devices with Secure Launch enabled from shutting down or entering hibernation.
On Patch Tuesday, it also resolved another known issue causing security applications to flag a core Windows component as vulnerable to memory corruption attacks.
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