Traveler 9.0.1.18 comes with a couple of minor fixes and a big change in the way Traveler Server access mail-databases. In 9.0.1.15 IBM introduced a new check if the Traveler server is listed in Trusted Servers (Server Security Tab) to show a warning if not. Now we know what IBM was preparing for.

Just got that question today at DNUG. There is an issue with the Notes Client with the current Windows 10 Update - aka Creators Update (Build 1703). According to the responsible person who is at DNUG today, this happens because of changed Windows graphics APIs. IBM is working on a fix which will be available in FP9.