If you cannot open Outlook 2016 rules anymore, if you get an error or the rules window does not appear then you can try the following to fix that.
Please note that this method will delete all your rules, so you will need to re-create them!
- Locate the Outlook.exe file (usually for the 32-bit Office 2016 it can be in this location C:\Program Files (x86)\Microsoft Office\root\Office16 or here for the 64-bit Office 2016 C:\Program Files\Microsoft Office\root\Office16
- Click the Windows search loupe near the Windows Start icon and type cmd then start Command Prompt
- Type the following command (change the path according to your outlook.exe location) including the quotes “C:\Program Files\Microsoft Office\root\Office16\outlook.exe” /cleanrules
- Start Outlook and now the rules should work.
If the Outlook Rules still don’t work then try to rename the files mentioned below and restart Outlook
Default outlook data Location: C:\Users\<username>\AppData\Roaming\Microsoft\Outlook\