I can't highlight with my mouse cursor in word documents

Use alternative selection methods first to confirm that text selection still works in Word, then address the likely causes of drag‑to‑select failing.

1. Test selection without dragging
   • Click at the start of a word, then hold Shift and click at the end of the word or paragraph. The text between should become selected.
   • Use keyboard navigation and selection:
     • Move by word: Option+Left/Right arrow.
     • Then hold Shift+Option+Left/Right arrow to extend the selection by words.
   • If these work, the issue is specifically with mouse/trackpad dragging, not with selection in general.
2. Check for common causes of drag issues Moderator guidance in similar Mac scenarios points to “simple reasons” for drag failures and recommends using the documented “Select Text” techniques instead of dragging. When dragging suddenly stops working, it is often due to:
   • Trackpad or mouse settings or gestures changing at the macOS level.
   • A conflict with other selection/interaction features (for example, features that change how clicks behave in the document area).
   Since Word for Mac does not expose the Windows-style File > Options path mentioned in some online posts, rely on macOS settings and Word’s built‑in selection alternatives instead of those Windows-only instructions.
3. Use more reliable selection techniques going forward The recommended approach in the referenced answers is to adopt more precise methods than dragging, which also work when dragging is unreliable:
   • Click once to place the cursor, then use Shift+Arrow keys to extend the selection.
   • Double-click a word to select it; triple‑click in a paragraph to select the entire paragraph.
   • Combine keyboard navigation (Option+Arrow, Page Up/Down, Home/End equivalents on Mac) with Shift to select larger ranges accurately.
4. If drag selection still does not work
   • Verify that drag‑to‑select works in other apps (which has already been done) to confirm it is Word‑specific.
   • If keyboard and click‑based selection work but dragging does not, and macOS input settings are correct, reinstalling or updating Word for Mac is often required.
   • If the issue persists after update/reinstall, use the documented selection techniques as a workaround and contact Microsoft support with details of the Mac model, macOS version, and Word version.

These steps allow selecting and editing text in Word documents even when the traditional click‑and‑drag highlight is not functioning.

References:

• I cannot copy text on word. I have a MacBook and I can highlight and copy on every other platform but Word. Any fix or solution? - Microsoft Q&A
• Cursor no longer working on Mac to highlight text in Word - Microsoft Q&A
• How do I select text with a trackpad? - Microsoft Q&A
• Keyboard shortcuts in Word

I'm not sure why the AI bot reply was marked as an Answer. It does nothing to correct the problem, it only suggests other methods for selecting text.

For actual cause & cure please see one of the existing threads on the issue such as Select Text. It also contains a link to another by the same name which describes a variety of text selection techniques which many users consider to be far more accurate and efficient than dragging, especially for long passages.