Job Interview for a CTO role for a premium employer, a big law firm.

All is going well, I am telling them about my years of experience doing complex software integrations in business environments. Talking CRM/ERP, project management and development with external service providers. I tell them I want a salary of 100k and they nod in silence.

Then out of the blue one of the three stakeholders/managers leans over for a final question:
"Soo, we have this really big IT problem and if you would happen to know a solution to it, you would really prove your worth: I have these 10k+ E-Mails in my Outlook folder which doubles as an archive and Outlook keeps getting slower all the time. What can we do?"