Classic Outlook replaces accented and extended characters with question marks

Last Updated: February 26, 2026

ISSUE

When you write extended characters in an email, you may find that they display as question marks.

Some examples that we have seen reported include registered trademark (®), accented characters (é, ü, ñ, etc.), pound currency (£), umlauts (¨ over a letter), and other Non-ASCII Symbols.

From the feedback so far, this issue is occurring in Version 2601 (Build 19628.20150+).

STATUS: INVESTIGATING

The Outlook Team identified the change that is causing this issue and is currently working on the fix. We do not have an ETA yet, but this is being worked on with priority. We will update this topic with the fixed builds and ETA as soon as they are available.

WORKAROUND

Workaround #1

Use Outlook Web Access (OWA) or New Outlook

Workaround #2

Disable Outlook automatically selecting the encoding for outgoing messages

Select File > Options > Advanced.
Under International Options, uncheck Automatically select encoding for outgoing messages.
Put a reminder on your calendar for March 10th to check back on this Known Issue to check the fix status. Once it is fixed you can switch it back to recheck Automatically select encoding for outgoing messages.

Workaround #3

Use UTF-8 for Outbound encoding

Select File> Options > Advanced.
Under International Options, note what your current setting is for Preferred encoding for outgoing messages: Add this to the reminder in Step 4.
Under International Options, change Preferred encoding for outgoing messages: Unicode (UTF-8)
Put a reminder on your calendar for March 10th to check back on this Known Issue to check the fix status. Once it is fixed you can switch it back. For example, many users will have Western European (ISO) by default. After you change the setting, it will now show:

Workaround #4

If you urgently need to work with the original settings in classic Outlook, you can revert to the prior version.

To revert to the prior Version 2512 (Build 19530.20184).

Open a Command Prompt in Administrator context.
Type or paste the command below into the Command Prompt window and press Enter:"%programfiles%\Common Files\Microsoft Shared\ClickToRun\officec2rclient.exe" /update user updatetoversion=16.0.19530.20184
To prevent Office updating back to the latest build, you can turn off updates by selecting File > Office Account > Update Options > Disable Updates.
Put a reminder on your calendar for March 10th to re-enable updates. Or check back on this Known Issue in case it is addressed sooner.