The January updates released a couple of weeks ago by Microsoft have proved to be problematic in a variety of ways. One of the numerous issues that people who installed the updates have been hit with has seen Outlook freezing.
It took a little while for Microsoft to acknowledge the issue, and after a few days investigating, the company managed to come up with a workaround. Now there is a proper fix available, and Microsoft has made it available as an out-of-band update.
The emergency fix was pushed out over the weekend – the nature and timing perhaps indicative of the scale and severity of the issue caused by the January update.
Microsoft has posted a note in the Windows message center reading:
Take Action: Out-of-band update to address cloud‑backed storage application issues
Microsoft released today a resolution for an issue observed after installing the January 2026 Windows security update. This issue may cause applications that open or save files stored in cloud‑backed locations to become unresponsive or display errors. Some installations of Outlook may also become unresponsive and fail to open when PST files are stored in cloud‑backed storage such as OneDrive.
An out-of-band (OOB) update was released today, January 24, 2026, to address this issue. This cumulative update includes all protections and improvements from the January 2026 Windows security update released January 13, 2026, as well as from the OOB update released on January 17, 2026 (which introduced fixes for two known issues: remote desktop connections and hibernation failures).
This OOB update is available through Windows Update for Windows 11 devices running the updates released this month. To install it, open Settings > Windows Update, and select Download and install. Note that this update will show up in Windows Update only if you have installed one of the updates released in January that caused this issue. Some devices may install the update automatically. For supported versions of Windows Server and Windows 10, the OOB update is available from the Microsoft Update Catalog.
In the release notes for the KB5078127 update for Windows 11 version 25H2 and Windows 11 version 24H2, Microsoft says:
This OOB update includes quality improvements. This update is cumulative and includes security fixes and improvements from the January 13, 2026, security update (KB5074109) and the out-of-band update (KB5077744) from January 17, 2026, in addition to the following:
- [File System] Fixed: After installing the Windows update released on and after January 13, 2026, some applications became unresponsive or encountered unexpected errors when opening files from or saving files to cloud-based storage, such as OneDrive or Dropbox. In certain Outlook configurations that store PST files on OneDrive, Outlook may hang and fail to reopen unless the process is terminated or the system is restarted. Users may also see missing sent Items or previously downloaded emails being re‑downloaded.
There are actually numerous versions of this out-of-band update available – each for a different edition of Windows. Bleeping Computer has compiled the following handy list:
- Windows 11 25H2 and 24H2: KB5078127 [Download Link]
- Windows 11 23H2: KB5078132 [Download Link]
- Windows 10 23H2 and 22H2: KB5078129 [Download Link]
- Windows Server 2022: KB5078136 [Download Link]
- Windows Server 2025: KB5078135 [Download Link]
- Windows Server 2019: KB5078131 [Download Link]
A manual installation of the fix is the only option for the time being, but Microsoft will be rolling up the patch in the February update – and it may also be included in the preview version.
Image credit: Davide Bonaldo / Dreamstime.com
