We have a number of Windows 2012R2 servers running a VB6 application that includes Crystal Reports 8.5 APIs and everything's been working fine. With 2012R2 going end of life soon, we've been switching the application onto 2016 servers.

Things are generally going well, except for some users that run reports and then export the data to CSV files. Export times have increased dramatically. In one case 5 minutes to 40 minutes, and in another 1.5 hours to 11 hours.

Does anyone have any idea what might be going on here? (and how we can fix it)