What Approved Sign Code Does and How to Stop It

Approved Sign Code is a Microsoft security feature that automatically signs outgoing emails with a digital certificate to prove they came from you and haven't been altered in transit. Once you turn it on in Outlook, it stays on by default for every message you send — unless you deliberately turn it off.

If you enabled it and now want to stop using it, you have two choices: disable it entirely so no emails get signed, or turn it off for individual messages. Which one you pick depends on whether your workplace requires it, whether your contacts can read signed emails, or whether you straightforward changed your mind about using it.

Key Takeaways

  • Approved Sign Code signs every outgoing email with a digital certificate once enabled, and stays on until you manually disable it.
  • You can turn off signing for all future emails in Outlook settings, or disable it for one message at a time before sending.
  • Disabling it does not erase signatures from emails you already sent — those remain signed.
  • If your organization requires Approved Sign Code for compliance, disabling it may violate policy or cause delivery problems.
  • Signed emails sometimes fail to display correctly in older email clients or webmail, which is a common reason people turn it off.

Disable Approved Sign Code for All Future Emails in Outlook Desktop

Open Outlook on your computer and go to File in the top menu. Select Options, then choose Trust Center from the left sidebar. Click the Trust Center Settings button.

In the Trust Center window, click Email Security on the left. Under the "Digitally sign outgoing messages" section, uncheck the box next to Sign outgoing messages. Click OK twice to save and close all windows. From that point forward, Outlook will not sign your emails unless you manually enable it for a specific message.

This change applies only to the Outlook account you are currently using. If you have multiple email accounts set up in Outlook, you will need to repeat these steps for each one if you want to disable signing on all of them.

Turn Off Signing for a Single Email Before Sending

If you want to keep Approved Sign Code enabled overall but send one unsigned email, open the message you are composing. In Outlook desktop, click the File tab at the top of the compose window, then select Properties.

Look for the Security Settings button and click it. Uncheck Add digital signature to this message, then click OK twice. Send the email normally — this message will not be signed, but future emails will be unless you repeat this process for each one.

In Outlook on the web, open a new message and look for the three-dot menu (more options) in the compose toolbar. Select Message settings, then toggle off Sign this message. The change applies only to that draft.

Why Signed Emails Sometimes Fail to Display Correctly

When you send a signed email, the recipient's email client has to verify the signature before displaying the message. Older versions of Outlook, Gmail, and some webmail services sometimes show signed emails as attachments or display them with extra formatting that looks broken.

If contacts are telling you they cannot read your emails or that they look strange, signing is often the culprit. Turning it off usually fixes the problem when ready. You can ask one of those contacts to reply to a test email after you disable signing — if it displays normally, you have found the issue.

Some organizations require signing for compliance reasons, so check with your IT department or manager before disabling it permanently. If your workplace requires it but your contacts cannot read signed emails, your IT team may need to adjust how the signature is applied or help recipients update their email software.

What Happens to Emails You Already Sent

Disabling Approved Sign Code does not remove signatures from emails you have already sent. Those messages remain signed and will continue to display as signed in recipients' inboxes. The change only affects new emails you compose after you disable the feature.

If a recipient is having trouble reading an old signed email, they cannot fix it by asking you to resend it unsigned — the original message is already in their mailbox. However, you can send them the same information in a new, unsigned email if they need it in a readable format.

Difference Between Approved Sign Code and Encryption

Approved Sign Code signs your email to prove it came from you and has not been changed. Encryption scrambles the message so only the intended recipient can read it. These are two separate features, and you can use one, both, or neither.

If you disable signing but still want to encrypt sensitive emails, you can keep encryption enabled in the same Trust Center settings. Conversely, you can sign emails without encrypting them. Check your organization's security policy to understand which features you are required to use.

Frequently Asked Questions

Will disabling Approved Sign Code cause problems with my email delivery?

Not usually. Disabling signing does not affect whether emails reach the inbox. However, if your organization requires signing for compliance or security policy, disabling it may violate those rules. Check with your IT department first if you work for a company with strict email security policies.

Can I turn off signing just for emails to certain people?

No. Approved Sign Code is either on for all recipients or off for all recipients in your settings. You can disable it for individual messages before sending, but you cannot create a rule that signs emails to some people and not others. If you need that level of control, contact your IT department about alternative signing solutions.

What if I disable signing and then want to turn it back on?

Go back to File > Options > Trust Center > Trust Center Settings > Email Security and check the box next to Sign outgoing messages. All future emails will be signed again. The process is the same whether you are re-enabling it or disabling it.

Does disabling Approved Sign Code affect emails I receive?

No. Turning off signing only stops you from signing outgoing emails. You can still receive and read signed emails from other people. Your email client will continue to verify their signatures automatically.

Why does my organization require Approved Sign Code?

Organizations use signing to prove that emails are authentic and have not been tampered with in transit. This is especially important in industries with strict compliance requirements, such as finance, healthcare, and law. If your workplace requires it, disabling it may trigger security alerts or violate policy.