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Why is Outlook displaying question marks instead of special characters?
The Text Encoding Bug
Since early February 2026, many Microsoft 365 users have reported that Classic Outlook replaces special characters with question marks. This text encoding error affects umlauts, accented letters, registered trademark symbols, and pound signs. Microsoft traced this bug to Outlook 365 version 2601, specifically build 19628.20150 and subsequent releases. The issue frequently occurs when sending messages to recipients hosted on US-based Microsoft servers.
Temporary Fixes for Outlook
Before an official patch existed, IT administrators relied on a manual configuration change to restore readability. You can adjust the default text encoding under your application settings by navigating to Options, then Advanced, and finally International Options. Switching the character set from Western European (ISO) to Unicode UTF-8 resolves the display issue for standard communications. However, automated systems like DocuWare still generate question marks even after applying this adjustment. To completely bypass the bug, administrators recommend temporarily using Outlook Web Access (OWA) or the New Outlook application.
Microsoft Issues Official Patch
Microsoft formally acknowledged the encoding defect on February 6, 2026, and updated their support documentation a month later to confirm an impending resolution. The permanent software fix arrives in the public updates scheduled for March 10, 2026. You must install one of the following builds to restore proper text formatting across your organization:
- Version 2601 (Build 19628.20252)
- Version 2602 (Build 19725.20164)
- Version 2603 (Build 19822.20032)
System administrators should verify the successful deployment of these updates across all workstations. Have you received the patch for Classic Outlook, and does your software display special characters correctly again?