User Configuration > Administrative Templates > Microsoft Excel 2016 > File Tab > Check Accessibility
User
HKCU\software\policies\microsoft\office\16.0\excel\accchecker
This policy setting allows you to configure whether Accessibility Checker will verify that tables do not have merged cells. If you enable this policy setting, no check will be made. If you disable or do not configure this policy setting, worksheets will be checked for merged cells and any issues will appear in the Accessibility Checker.