For whatever reason SharePoint search is not indexing .docx or .pptx files. Excel, pdf, web etc all work fine.
I've tried creating a new doc lib, creating a new word doc via the 'New' button in SP and doing the same with Excel, Excel will show in the search results and the word doc will not.
Searching for FileType:docx returns nothing.
The docs have been in SP for quite a week or so. I have forced a re-index many times.
Other than a few managed properties nothing has been changed in Search config, it's a new tenant.
UPDATE: I've just gone through the rather long winded process to get the search logs and find this error on docx and pptx files.
Processing this item failed because of a Word parser error. ( Could not load file or assembly 'DocumentFormat.OpenXml, Version=18.104.22.168, Culture=neutral, PublicKeyToken=f300afd708cefcd3' or one of its dependencies. The system cannot find the file specified.; SearchID = 60B743A0-C83E-44E6-B9F0-510014DEAE92 )