If encountering this problem in Word 2016 - known issue after installing KB 3213656 (August 8) or KB 4011039 (September 5).
After installing the August 8, 2017, update for Word 2016 (KB3213656) or the September 5, 2017, update for Word 2016 (KB4011039), you may encounter the following issues:
If you merge vertical cells in a table, the cell content disappears, and you can’t select the merged cell.
If you open an existing document that has a table with merged cells, the cells will appear to be blank.
This issue occurs only for those who receive Office 2016 updates using Windows Installer technology (MSI). If you have a Click-to-Run edition of Office, such as Office 365 Personal, you won’t encounter this issue.
As a workaround, you can uninstall both KBs and your tables will return to normal. We anticipate releasing the fix for this issue in the next monthly update, tentatively scheduled for October 3, 2017.
Follow the steps below on how to uninstall an update on Windows 10:
- Close Word 2016.
- Select the Start button. Go to Settings > Update &
security > Update history > Uninstall updates.
- Look for KB3213656 and KB4011039.
- Select the updates and then click Uninstall.
- Click Yes or enter the administrator password to proceed with the removal
- Wait for the process to complete.