How can I preclude border agents from seeing emails on my laptop? [closed]

I use Microsoft Outlook 2016 (abbreviated to O16) on my Windows 10 laptop that stores all emails offline, without Internet access. Canadian and US border agents are legally empowered to demand your password (See this and this): thus how can I legally preclude border agents from seeing my emails by clicking on O16?

1. Using another computer for me is impossible, partly because uploading some documents online (e.g. to OneDrive or some online server) can threaten their security and privacy too.
2. The only option that dawned on me, is to delete O16 entirely before crossing the border, and then reinstalling it after crossing successfully.
3. Is there any other more efficient option?