in case it helps others not waste many hours trying to resolve issues with Office (especially Word and Excel) when saving, but also with general usage, there is a current bug in MBAM in how it protects Office applications caused by the Creators Update.
MalwareBytes is suggesting turning off Word and Excel protection (in Settings, Protection, Manage Protected Applications) until the next release (released as Beta today).
It only affects WIn10 with CU, MBAM Premium and Office 2013 and 2016 (standalone or 365) users.
Cost me roughly 20 hours over two days figuring out why my Excel spreadsheet was getting corrupted and blaming my VBA macros and/or Office.
Turns out it is MBAM, but in their defence, in turn because of MS.
MBAM thread here; https://forums.malwarebytes.com/topic/199341-mbam-306-and-office-2016-with-win10-creators-update/
and for those interested, or affected, the Beta release is here; https://forums.malwarebytes.com/topic/200230-malwarebytes-version-310-beta-available-for-download/