Linux Only - Particularly relevant if you have a discrete graphics card
Office 2016 and Office 365 sometimes have graphics problems including the cryptic "black screen" that can be solved by forcing the applications to use software rendering. We added a configuration option in CrossOver 18 which allows Linux environment variables to be set for a single bottle. The configuration settings are stored in ~/.cxoffice/(your Office bottle)/cxbottle.conf
If you are familiar with using the terminal, simply edit that file and add the "LibGL_Always_Software" environment variable as a new line under [EnvironmentVariables] after the line listing the App ID. It should look like this:
[EnvironmentVariables] "CX_BOTTLE_CREATOR_APPID" = "com.codeweavers.c4.14101" "LIBGL_ALWAYS_SOFTWARE" = "1"
If you are unfamiliar with using terminal to edit, then you can find this file by turning on the option to show hidden files. This will vary by distro, but for Ubuntu, simply open "Files," click on the "hamburger menu" (3 horizontal lines), and click the check mark to show hidden files. You can then navigate to the Home folder and then navigate to .cxoffice/(your Office bottle) and open cxbottle.conf with a graphical text editor.