New Outlook Deleted All my Signatures and Won't let me Add Them Back

New Outlook and Outlook on the web support multiple signatures, so being restricted to one in both clients is not expected behavior and should be escalated as a mailbox/cloud-signature problem after preserving and recreating any recoverable signature content.

Recover the deleted signature content

Outlook does not provide a documented restore or recycle-bin function for deleted signatures. Check these sources before rebuilding them:

1. Open a previously sent message containing each old signature.
2. Copy the complete rendered signature—not HTML source—including its text, links, and images.
3. Paste each version into Word or another document temporarily, so it is preserved while troubleshooting.
4. Also check another computer, phone, or classic Outlook installation where the signatures might still exist. Do not edit them there until their content has been copied.

Signatures created only “on this device” in classic Outlook may not be available on another device. Cloud-managed signatures are intended to be available across supported Outlook experiences.^1^

Recreate multiple signatures

In either new Outlook or Outlook on the web:

1. Open Settings.
2. Select Accounts → Signatures.
3. If several accounts appear, select the affected work account.
4. Select Add signature.
5. Give it a distinct name, paste the preserved content, and select Save.
6. Repeat Add signature for each additional version.
7. To use one manually, open New mail → Message → Signature, then select the required signature.

Microsoft explicitly documents that new Outlook can store various signatures and that Outlook on the web can create multiple named signatures.^1^

Because this already fails in both the app and web version, reinstalling or resetting only the Windows app is unlikely to address the cross-client state.

If the second signature disappears or cannot be saved

Microsoft previously documented a cloud-signature issue in which newly created signatures were deleted after a while or failed to synchronize with Outlook on the web. That specific issue was fixed in supported Outlook builds, but older cached account data could remain affected.^2^

For a business account, ask the Microsoft 365 administrator to:

• Check Microsoft 365 admin center → Health → Service health for an active Exchange Online or Outlook incident.
• Open a Microsoft 365 support request if no incident appears, stating:
  • Existing cloud signatures disappeared.
  • Only one signature can be saved.
  • The behavior occurs in both new Outlook and Outlook on the web.
  • The affected mailbox and approximate date the signatures vanished.
• Check whether an Outlook web app mailbox policy controls signatures. Administrators can disable signature creation through Set-OwaMailboxPolicy or the Exchange admin center.^3^ A fully disabled policy normally prevents manual signature creation, so it is less consistent with being able to save exactly one.

Conditional cached-settings workaround

Use this only if classic Outlook for Microsoft 365 is also installed and newly created signatures disappear after synchronization. Microsoft documents renaming this registry key as a workaround for stale cloud-settings cache:

HKEY_CURRENT_USER\Software\Microsoft\Office\Outlook\Settings

Close Outlook, rename Settings to Settings_old, and restart Outlook.^2^

Editing the registry can reset cached Outlook settings; export the key first or have the organization’s IT administrator perform the change. Since the web client is also affected, support escalation should come before this local workaround.

References

1. How to add and change an email signature in Outlook
2. Signatures are not syncing between Outlook Desktop and Outlook Web App ...
3. Policy Management in new Outlook for Windows