Having Windows Outlook access problems? An update might have caused it.

A Windows Server security update, to be exact.
 By 
Alex Perry
 on 
Microsoft Outlook logo on phone screen
There isn't a real fix yet. Credit: Thomas Fuller/SOPA Images/LightRocket via Getty Images

Microsoft may have borked Outlook for some folks with a new Windows update.

Specifically, a Windows Server security update has caused access issues for Outlook on some Exchange Server systems, according to a Microsoft security note (cited by BleepingComputer). This is specifically affecting systems running Windows Server 2019 and later, per Microsoft. As a result, users may not be able to access Outlook, or sent messages might just remain in the Outlook outbox without actually going anywhere.

There is no firm fix for this problem just yet. Microsoft says that the severity of the problem will differ from server to server, with some not encountering any problems at all. In a different post, Microsoft urged users not to uninstall the problematic update, instead offering a workaround:


You May Also Like

  1. Open an elevated Command Prompt on an Exchange Server

  2. Enter the following as a command: "reg add "HKLM\SOFTWARE\Microsoft\Rpc" /v EpmapSavedContextCap /t REG_DWORD /d 65536 /f"

  3. Reboot the server

That should help alleviate the issue until Microsoft offers a long-term fix for it.

Want to learn more about getting the best out of your tech? Sign up for Mashable's Top Stories and Deals newsletters or get Mashable push alerts today. 

journalist alex perry looking at a smartphone
Alex Perry
Tech Reporter

Alex Perry is a tech reporter at Mashable who primarily covers video games and consumer tech. Alex has spent most of the last decade reviewing games, smartphones, headphones, and laptops, and he doesn’t plan on stopping anytime soon. He is also a Pisces, a cat lover, and a Kansas City sports fan. Alex can be found on Bluesky at yelix.bsky.social.

Mashable Potato

Recommended For You
Microsoft responds to Microsoft 365 problems affecting email, Teams, and OneDrive
a yellow cab moves at a blur in front of microsoft office headquarters

Microsoft Outlook outage reported by thousands of users on Monday
illustration of utility workers next to a laptop with the microsoft outlook logo

Windows 11 update reduces RAM usage
Windows 11 on laptop



Trending on Mashable
NYT Connections hints today: Clues, answers for November 1, 2026
Connections game on a smartphone

Wordle today: Answer, hints for November 1, 2026
Wordle game on a smartphone

NYT Connections hints today: Meanings for each word for Nov. 1, 2026
NYT Connections logo.

NYT Strands hints, answers for November 1, 2026
A game being played on a smartphone.

NYT Connections hints today: Clues, answers for October 31, 2026
Connections game on a smartphone