Office documents are not rendering as expected

ISSUE

If you're using Office for Mac version 15 or lower (builds < 16.16.xxxx) and you try to open an Office for Mac version 16 document (builds >= 16.16.xxxx), it might not render as expected and may cause layout issues.

This unexpected rendering is due to changes in how font names are saved in files for the newest version of Office for Mac. This change provides a better cross-platform experience and allows text to be rendered the same across all operating systems.

TECHNICAL DETAILS

Office saves the name of the font in the document when a font is applied to the content. This font name could be different between macOS and non-macOS apps because of the values defined by the font creators in font tables. As apps try to load fonts using a name saved on a different platform (i.e. Word for Microsoft Windows tries to load font using a name that was written by Word for Mac), it may cause font substitution rendering issues during cross-platform file sharing and co-authoring.

Office for Mac has switched to a uniform way of writing font names so text will be rendered correctly regardless of the OS. Previously, Office for Mac wrote “macOS” font names and now, it writes “Win” font names to be aligned with the behavior in non-macOS Office apps. This way, any new content will be saved in a consistent manner across platforms.

Other platforms, including iOS, are already using the ‘Win’ format to write font names. No action is required from the user to take advantage of this change. Once you update to build 16.38.530 or later, Office makes the changes for you. Office will replace all saved “macOS” font names to “Win” names to spare you from having to re-apply every font. This is a one-time change as documents having macOS fonts names are converted to Win font names. This whole-document font name replacement would be only carried out after any edits are applied to the document to prevent document modification when there are no changes.

As a result of this change, these updated documents when shared with older Office for Mac clients (i.e. builds < 16.16.xxx), may not render correctly as they are expecting the traditional ‘macOS’ font names. You can continue to read and edit content; however, the content is rendered using a substitute font.

STATUS: INVESTIGATING

The Office team is aware of this issue and currently working on a fix. We will update this article with more information as it becomes available.