Why This Happens
Excel opens, your spreadsheet is there, but clicking a cell and typing does nothing — while Word, PowerPoint and Outlook all work normally. This is almost always caused by a corrupted Excel preferences file. Each Office app keeps its own separate preferences file, which is why only Excel is affected.
The fix is to delete that file. Excel builds a fresh one automatically the next time it opens.
Reset Excel's Preferences File
First, quit Excel completely — click Excel in the menu bar and choose Quit Excel, or press Cmd + Q.
Click the Finder icon in your Dock (the blue square with the smiley face) so that Finder becomes the active app.
In the menu bar at the top of your screen, click Go — it sits between View and Window.
Choose Go to Folder... from the dropdown. A small box will appear.
Paste this path into the box:
~/Library/Containers/com.microsoft.Excel/Data/Library/Preferences
Press Return. Finder opens that folder directly.
Find the file
com.microsoft.Excel.plistand move it to the Trash.Open Excel again and try typing in a cell.
This only resets Excel's own app preferences, such as recent-file lists and view settings. Your spreadsheets, your product key and your other Office apps are not affected.
If Excel Still Won't Let You Type
Go back to the same folder and check whether com.microsoft.Excel.plist is there again. The file doesn't always get deleted on the first try. If you see it, move it to the Trash once more and restart Excel — the second attempt usually resolves it.
Still no luck after two attempts? Get in touch with our support team, via chat icon in the bottom-right corner and we'll take a look together.