1. Open outlook on your computer.
2, click on the file
3. Click Options
4. Click on the email
5. Click on the signature
6. Click the new signature name.
7. Enter the e-mail signature
8. Click Save after setting.
One: Enter the safe mode and open Outlook to see if it can pop up: Press the key combination of "Win+R", type "outlook /safe" and press enter.
Two: If the pop-up box pops up normally, you can disable the add-in as follows: Click the File tab-Options-Add-ins -Go- Unselected Add-ins-OK.