After an upgrade to windows 10 LTSB 2016 “anniversary” edition MS word is giving the error:
“Word could not create the work file. Check the temp environment variable”

According to Microsoft this error occurs when Word doesn’t have permission to write temporary files. To fix this they suggest changing the location of the Internet Explorer Temporary folder or change the registry pointer for Word to a correct temporary location with:
HKEY_CURRENT_USER \Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders
Set the “Cache” to:
%USERPROFILE%\AppData\Local\Microsoft\Windows\Temporary Internet Files

For Details See: https://support.microsoft.com/en-us/kb/2285187