Outlook Signature Changes Back After Restart: Fix

You edit your email signature in Outlook, save it, and close the program. When you restart Outlook, the signature reverts to the old version. This problem happens because Outlook stores signatures in a local folder on your computer, and the changes you made are overwritten by a cached copy or by a sync issue with Microsoft 365. This article explains why the signature resets and provides the exact steps to stop it from reverting after a restart.

Why Outlook Reverts Your Signature to an Older Version

Outlook stores each signature as three files in a local folder: an HTML file, a plain text file (TXT), and a Rich Text Format file (RTF). When you create or edit a signature, Outlook writes new content to these three files. If the files become corrupted or if Outlook cannot write to them properly, the program falls back to a cached version of the signature stored in memory or in a separate backup location.

A second cause involves roaming signatures in Microsoft 365. If your Exchange Online mailbox has the roaming signatures feature enabled, the server stores a copy of your signature. Every time Outlook starts, it downloads the server copy. If the server copy is older than the local copy, the server overwrites your local changes. This happens most often when you edit the signature on one computer and then open Outlook on a different computer that has not synced the change.

A third cause is a corrupted NormalEmail.dotm template. This Word template stores default formatting for email messages, including signature styles. If the template is damaged, Outlook may replace your signature with a default or blank version.

Steps to Stop Outlook From Resetting Your Signature

Complete the following steps in order. Test Outlook after each step by restarting the program. If the signature still reverts, move to the next step.

Step 1: Delete the Signature Files and Recreate Them

1. Close Outlook completely
   Make sure Outlook is not running. Open Task Manager and end the Outlook process if it appears in the Processes tab.
2. Open the Signatures folder
   Press Windows Key + R, type %appdata%\Microsoft\Signatures, and press Enter. This opens the folder where Outlook stores signature files.
3. Back up your current signatures
   Right-click inside the folder, select New > Folder, and name it Backup. Drag all files and subfolders into the Backup folder. Do not delete the Backup folder yet.
4. Delete the original signature folders
   Select all folders inside the Signatures folder except the Backup folder. Press Delete. If you have only one signature, you will see three files with the same name but different extensions (.htm, .txt, .rtf). Delete those files.
5. Open Outlook and create a new signature
   Go to File > Options > Mail > Signatures. Click New, type a name for the signature, and create your signature content. Click OK and then OK again.
6. Restart Outlook
   Close Outlook and open it again. Check if the signature stays the same. If it does not revert, the problem is solved. If it reverts, proceed to Step 2.

Step 2: Clear the Roaming Signature Cache Using Registry

This step forces Outlook to ignore the server-side signature and use only the local files. Editing the registry incorrectly can damage your Windows installation. Back up the registry before making changes.

1. Close Outlook
   Ensure Outlook is not running.
2. Open Registry Editor
   Press Windows Key + R, type regedit, and press Enter. Click Yes in the User Account Control prompt.
3. Navigate to the Outlook registry key
   Go to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences. For Outlook 2019 or Microsoft 365, use 16.0. For Outlook 2016, also use 16.0. For Outlook 2013, use 15.0.
4. Create a new DWORD value
   Right-click in the right pane, select New > DWORD (32-bit) Value. Name it ForceClientSignature.
5. Set the value to 1
   Double-click the new entry, set Value data to 1, and click OK.
6. Restart Outlook
   Close and reopen Outlook. Check whether the signature stays after a restart.

Step 3: Disable Roaming Signatures in Exchange Online

If you use Microsoft 365 with Exchange Online, the roaming signature feature may be active. Disable it using the Exchange admin center or PowerShell.

1. Open Exchange admin center
   Go to https://admin.exchange.microsoft.com and sign in with your administrator account.
2. Go to Mailboxes
   In the left menu, select Recipients > Mailboxes. Click the mailbox of the user who has the signature issue.
3. Open mailbox properties
   In the user details pane, click Mailbox features.
4. Disable roaming signatures
   Under Email connectivity, find Roaming Signatures. Click Disable. Confirm the change.
5. Restart Outlook
   Close and reopen Outlook. Verify the signature no longer reverts.

Step 4: Rename NormalEmail.dotm Template

1. Close Outlook
   Make sure Outlook is closed.
2. Open the Word Startup folder
   Press Windows Key + R, type %appdata%\Microsoft\Word\STARTUP, and press Enter.
3. Rename NormalEmail.dotm
   If the file exists, right-click it and select Rename. Change the name to NormalEmail.old.
4. Restart Outlook
   Open Outlook. The program creates a new, clean NormalEmail.dotm file. Check if the signature problem is resolved.

If Outlook Still Reverts the Signature After the Main Fix

Signature reverts only on one specific email account

If the signature reverts only when you compose from a specific account, the account may have a server-side signature policy applied by your IT department. Contact your Exchange administrator. Ask them to check the mailbox policy for the attribute Signature in the Exchange admin center. If a policy forces a signature, you cannot change it locally.

Signature changes back after a Windows update

Windows updates sometimes reset file permissions on the AppData folder. If the Signatures folder loses write permissions, Outlook cannot save your edits. Right-click the Signatures folder, select Properties > Security. Ensure your user account has Full control. If not, click Edit, select your user, check Full control, and click OK. Restart Outlook.

Signature reverts in Outlook for Mac

Outlook for Mac stores signatures differently. The registry fix and Exchange roaming signature disable apply only to Windows. On Mac, go to Outlook > Preferences > Signatures. Delete the signature and create a new one. If it reverts, contact your Exchange administrator to disable roaming signatures for your mailbox.

Local Signature vs Roaming Signature: Key Differences

Item	Local Signature	Roaming Signature
Storage location	%appdata%\Microsoft\Signatures folder on the local computer	Stored on the Exchange Online server and synced to all devices
Edit behavior	Changes are saved only on the local machine	Changes are saved on the server and pushed to every device that signs in
Conflict handling	No conflict unless multiple profiles access the same folder	Server version overwrites local version on each Outlook restart
Best for	Single-computer users or users who do not need synced signatures	Users who switch between multiple computers and want the same signature everywhere

You can now control whether your signature stays after a restart by clearing the local cache, using the ForceClientSignature registry key, or disabling roaming signatures in Exchange Online. If the problem continues, check file permissions on the Signatures folder. For advanced users, consider creating a Group Policy Object that sets ForceClientSignature to 1 for all domain-joined computers.