Key facts
- MIME type application/vnd.openxmlformats-officedocument.wordprocessingml.document.
- Actually a ZIP archive of XML parts: word/document.xml holds the text, with styles, images (word/media/) and [Content_Types].xml alongside.
- Standardized as ECMA-376 and ISO/IEC 29500; .docm is the macro-enabled variant.
- Text-only documents are often 15-50 KB; embedded images make up most of larger files.
How to open a .docx file
Windows
Open it in Microsoft Word or for free in Word for the web (office.com) or LibreOffice Writer. WordPad, which once opened DOCX, was removed in Windows 11 24H2.
macOS
Open it in Pages (free), Word for Mac or LibreOffice. Quick Look and TextEdit show the text with basic formatting.
Linux
Open it in LibreOffice Writer, or convert from the terminal with libreoffice --headless --convert-to pdf report.docx.
Common problems and fixes
- 'Word found unreadable content' or the file will not open
- Let Word recover it, or use File > Open, select the file, click the arrow beside Open and choose Open and Repair. LibreOffice can often open files Word refuses.
- DOCX is corrupt after download or email
- The ZIP container is likely truncated. Test it with unzip -t report.docx; if entries fail, re-download it, or rename a copy to .zip and extract word/document.xml to rescue the text.
- Opens in Protected View or editing is disabled
- Windows marks files from the internet. If you trust the source, click Enable Editing, or right-click the file > Properties > Unblock.
- Layout or fonts look different on another computer
- The fonts are missing or a different app is rendering it. Embed fonts (File > Options > Save in Word) or send a PDF for a fixed layout.
Often converted to or from: PDF, DOC, ODT, TXT, HTML, Markdown