Unable to edit Subject line in Outlook email

Unable to edit Subject line in Outlook email installed on your Windows 11 or Windows 10 computer and you use Outlook, you can perform certain actions like edit received email, insert an emoji or image in the email subject line or body and so on. Now for some reason, if you’re unable to edit the subject line in Outlook email, this post shows you how to do it.

If you have Microsoft Office or Microsoft 365 installed on your Windows 11 or Windows 10 computer and you use Outlook, you can edit received email, insert an emoji or image in the email subject line or body and so on. However, if you’re unable to edit the subject line in Outlook email, this post shows you how to do it.

Related Post: The file cannot be opened message in Outlook 

Unable to edit Subject line in Outlook email

The text cursor does not appear when you open a message in Outlook and select the subject, preventing you from editing the subject line of the message. This behavior occurs in Outlook 2013 Service Pack 1 and newer versions when the message header is collapsed to compact the size of the message.

So you can’t edit the subject line in an Outlook email when the message header is collapsed. In Outlook 2013, the default behavior is the expanded header, while in Outlook 2016, the default behavior is the collapsed header.

If you have ever written an email in Outlook, you know that the Infobar, which contains the To, Subject, and other fields, can be a bit small.

1. Registry Editor
2. REG (registry) file
3. Command Prompt

Let’s see the description of the methods in detail.

1] Via Registry Editor

To always expand the email message header in Outlook on Windows 11/10, do the following. Since this registry operation can affect your system, it’s recommended that you create a backup or restore point before proceeding.

• Open the Run dialog To open the Run dialog, press the Windows key + R.
• To open Registry Editor, type reged it in the Run dialog box and hit Enter.
• Navigate or jump to the registry key path below: Use the navigation pane or jump to the registry key path below:

Note: The placeholder x.0 denotes the version of Office Outlook (Outlook 2010 = 14.0, Outlook 2013 = 15.0, Outlook for Microsoft 365, 2019, 2016, 2021 = 16.0) that you’re using on your system.

• At the location, double-click the “Mini mal Header On” entry on the right pane to edit its properties.
• Now, enter “1” in the Value data field to collapse the folder, or “0” to expand it.
• Click OK or hit Enter to save the change.
• Exit Registry Editor To exit Registry Editor, click File > Exit.

2] Using .REG (registry) file

The preferred setting for the Mini mal Header On registry key is 1.Alternatively, you can set the Mini mal Header On registry key value to 1 to achieve the same outcome.

To open the Run dialog, press the Windows key + R on your keyboard.
To open Notepad, in the Run dialog box, type notepad and hit Enter.
Copy and paste the code below into the text editor and make sure to replace the x.0 placeholder with the actual Outlook version number:

For always collapsed

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\x.0\Outlook\Options\Mail] “Mini mal Header On”=dword:00000001

For always expanded

Windows Registry Editor Version 5.00

[HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Office\x.0\Outlook\Options\Mail] “Mini mal Header On”=dword:00000000

Now, select the File option from the menu and click the Save As button.
Choose a location to save the file (preferably desktop).
Create a file with a .reg extension that contains your preferred Outlook behavior.
Choose “All Files” from the “Save as type” drop-down list.
Exit Notepad.
Now, to merge the saved .reg file, double-click it.
Click Run > Yes (UAC) > Yes > OK to approve the merge.

3] Via Command Prompt

Minimal Header On Similarly, you can set the preferred Mini mal Header On registry key value by editing the registry. Here’s how:

• To open the Run dialog, press Windows key + R.
• Type ‘cmd’ into the Run dialog box, and then press CTRL + SHIFT + ENTER to open Command Prompt in admin/elevated mode.
• In the command prompt window, copy and paste the command below and hit Enter. Make sure to replace the x.0 placeholder with the actual Outlook version number:

For always collapsed

reg.exe Add “HKCU\SOFTWARE\Policies\Microsoft\Office\x.0\Outlook\Options\Mail” /V “MinimalHeaderOn” /T REG_DWORD /D “1”

For always expanded

reg.exe Add “HKCU\SOFTWARE\Policies\Microsoft\Office\x.0\Outlook\Options\Mail” /V “MinimalHeaderOn” /T REG_DWORD /D “0”

• Exit CMD prompt after the command has executed.

How do I make the subject line in Outlook editable?

EditTo edit an email subject line in Outlook, follow these steps:

1. Open Outlook.
2. Select the email you want to edit.
3. Click on the “Subject” field.
4. Type in the new subject.
5. Press “Enter” to save your changes.

Why can’t I change the subject line in Outlook 365?

If the message header is collapsed in Outlook 365 on your Windows 11/10 PC, you won’t be able to change the subject line. To expand the header, go to the extreme lower right of the header and click on the small “down arrow.” Once the header is expanded, you can change the subject line. Remember that the header’s state is persistent, so you’ll only need to do this once.

Can you edit the subject line in Outlook 365?

Click on the subject line of the message to change it. Press CTRL + A to select the entire subject line. Type your new subject and click the Save icon in the top left corner of the message window. Close the message.