This problem has been reported many times before. It is present in every version of MS Word for macOS after 16.49 up to the current 16.89.1, on macOS 10.14 Mojave or later up to macOS 15 Sequoia. It occurs whenever there is no 'Metal' graphics acceleration present.
That's why it is easy to reproduce, just following the first advice above:
- Start up your Mac in Safe Mode, open a Word Document, and select some text.
Instead of highlighting the selection, a solid grey box will appear, that covers the selection area.
The bug:
Word since version 16.50 seems to use a Metal Shader to draw the translucent selection highlight by default and sadly assumes the presence of Metal graphics acceleration without actually checking for it.
The solution:
Word should check for the availability of Metal, and if not present, fall back to the older method of highlighting the selection (that btw all other Office for Mac Apps are still using).
The most common reasons for Metal acceleration not being present are:
- Mac started up in Safe Mode, therefore disabling all graphics acceleration.
- Mac with a pre-Metal graphics card running macOS 10.14 or later (eg by means of OCLP).
Please fix this long standing software bug in MS Word ASAP.
Thank you!