Overview

When using Kerio Outlook Connector with recent versions of Microsoft Outlook 365, email signatures may fail to function correctly if the Kerio Connect user's Full Name (Display Name) contains Unicode characters such as diacritics or special symbols.

Common symptoms include:

• Signature editor fails to initialize or open
• Signatures cannot be created or saved
• Automatic signature insertion does not work
• Default signature settings do not persist after restarting Outlook
• No error message is displayed to the user

Examples of problematic Full Names:

• Tomáš Šperka
• José García
• Müller, François
• Any name containing diacritics ( á, é, í, ó, ú, ñ, ü, ö, č, š, ž, etc.) or special symbols

Root Cause

Starting with Microsoft Outlook Version 2303 and newer (including Outlook 2024), Microsoft introduced account-associated roaming signature migration. Outlook now derives signature filenames and folder mappings from the account identity string.

When the account identity contains a display name with Unicode characters or special symbols, Outlook encodes these characters in the signature folder and file paths. This encoding prevents Outlook from correctly locating and managing signatures, causing the signature functionality to fail silently.

The signature files and folders are stored in %APPDATA%\Microsoft\Signatures with encoded names that Outlook cannot properly match to the account identity, leading to initialization failures.

Solution

The Kerio development team has identified and resolved this issue. A fix is will be included in a future generally available Kerio Outlook Connector build.

Step 1: Verify Current KOFF Version

1. Open Microsoft Outlook
2. Go to File → Account Settings → Account Settings
3. Check the version of Kerio Outlook Connector currently installed

Step 2: Download and Install Updated KOFF

1. Download the latest Kerio Outlook Connector from this temp Google Drive folder
2. Close Outlook completely before installation
3. Run the KOFF installer with administrative privileges
4. Follow the installation wizard to complete the upgrade
5. Restart Outlook after installation

Step 3: Test Signature Functionality

1. In Outlook, go to File → Options → Mail → Signatures
2. Create a new signature or edit an existing one
3. Set the default signature for new messages and replies/forwards
4. Restart Outlook and verify that default signature settings persist
5. Compose a new email and confirm the signature is automatically inserted

Workaround (Temporary)

If you cannot immediately upgrade KOFF, you can use the following temporary workaround:

1. Log in to Kerio Connect Administration Console
2. Navigate to Accounts → Users
3. Select the affected user account
4. Edit the user's Full Name field to use only ASCII characters (A-Z, a-z, 0-9, spaces, basic punctuation)
5. Example: Change "Tomáš Šperka" to "Tomas Sperka"
6. Click OK to save changes
7. Have the user restart Outlook
8. Test signature creation and automatic insertion

Summary

Outlook signature issues with Unicode characters in user display names are caused by Microsoft Outlook's roaming signature feature introduced in version 2303+. The issue has been resolved in Kerio Outlook Connector 10.0.8 patch 2 and later versions. Upgrading KOFF on affected client machines (no server upgrade required) resolves the issue permanently. As a temporary workaround, changing the Kerio user Full Name to ASCII-only characters will restore signature functionality.

FAQ

Q1: Do I need to upgrade my Kerio Connect server to fix this issue?

No, you do not need to upgrade the Kerio Connect server. Only the Kerio Outlook Connector (KOFF) on client machines needs to be updated to version 10.0.8 patch 2 or higher.

Q2: Why does changing the Full Name to ASCII characters fix the problem?

When the Full Name contains only ASCII characters, Microsoft Outlook does not encode the signature folder paths, allowing Outlook to correctly match the account identity to the signature files. This prevents the initialization failure that occurs with Unicode characters.

Q3: Will changing the Full Name to ASCII affect email functionality or user experience?

No. The Full Name field change only affects the internal account identity used by Kerio Outlook Connector. Users can still send and receive emails normally, and Unicode characters can be used freely in email content, subject lines, and display names shown to recipients. The workaround only impacts the signature initialization mechanism.