Yeah, well... Just don't assume the doc/docx file you are working on with multiple revisions and comments and you are dutifully saving every 5 minutes will open next time you try loading it... Libreoffice will eat your document sooner or later if you edit a word file [0].
Switch to Libreoffice file format then convert to doc/docx then send back that doc/docx file.
[0] it's sneaky, basically Libreoffice will show you your edits and let you manipulate and modify the document as wish but what it saves into the file is corrupted and you will only notice it next time you open that file. Sometimes it's a mismatched tag in the internal xml representation (can be fixed), sometimes huge chunk of the doc will be missing (can't be fixed).
Switch to Libreoffice file format then convert to doc/docx then send back that doc/docx file.
[0] it's sneaky, basically Libreoffice will show you your edits and let you manipulate and modify the document as wish but what it saves into the file is corrupted and you will only notice it next time you open that file. Sometimes it's a mismatched tag in the internal xml representation (can be fixed), sometimes huge chunk of the doc will be missing (can't be fixed).