
Hello ArielA. I have found an article which is similar with your issue and was answered by an author and provided instruction how to fix it. You may try this instruction below:
- In Finder, right-click the file and choose Open With > Pages.
- The document will launch in Pages. Pages must identify a problem with the file and allow you to explore previous versions of it. If this option isn’t available, navigate to File > Revert To > Browse All Versions.
- With the Browse All Versions panes opened, on the right side, utilize the arrows to navigate back to a date prior to when the file got corrupted.
- Press the Restore button.
- Then the crucial step is to do not store the document. Just close the document.
- Returning to the Finder, you should now be able to access the file in Word.
- If Word continues to show the same error message, repeat the instructions above, and when you’re back in the Browse All Versions pane, go back a bit further in time, restore that version, and attempt it again.
If you unintentionally save the document in Pages, it will store the file in the Pages format. To return it to the Word format, you can repeat the previous steps to revert the file to an earlier version, or you can export the document back to Word.
Here's the reference: Solution to "Word found unreadable content..." error message
Best regards,