Windows 10 High Contrast or Custom Theme mode prevents Outlook startup

Symptom: Out'n About! for Outlook addin stops Outlook from starting up. Outlook may stop loading at "Loading 2 of 3 add-ins" or "Loading Profile" steps. Fix: If you are having issues with loading the Out'n About! for Outlook add-in, please check if the affected user(s) have High Contrast mode enabled. Try closing Outlook, and disabling High Contrast Mode. Also, sometimes a custom Windows Theme may also prevent Out'n About from loading. Please try closing Outlook, and switch to a default Windows...