Excel Not Responding: what to do right now, and how to stop it

The title bar says “(Not Responding)” and nothing moves. Here is what to do, in order.

Right now: do not force-close yet

1. Wait 60 seconds. Excel is often busy, not dead — a big paste, a recalculation, a save to OneDrive.
2. Look at the bottom-left. “Calculating (4 processors): 37%” means it is working. Let it finish.
3. Still frozen after two minutes? Press Ctrl + Alt + Delete › Task Manager, select Excel, End task.
4. Reopen Excel. The Document Recovery panel on the left lists AutoRecover copies. Open the newest, save it under a new name.

Then: find the cause

1. An add-in

The most common cause. File › Options › Add-ins › at the bottom, Manage: COM Add-ins › Go › untick all › OK. Restart Excel. If the freezing stops, re-tick them one at a time to find the culprit.

2. A huge file

Press Ctrl + End. If it lands far below your data, Excel thinks the sheet is enormous. Delete the empty rows and columns after your data (select, right-click › Delete), then save.

3. Volatile formulas

Thousands of TODAY(), OFFSET, INDIRECT or whole-column SUMIF(A:A,…) formulas recalculate on every change. Set Formulas › Calculation Options › Manual while editing, press F9 when you need results.

4. Conditional formatting sprawl

Copy-pasting rows multiplies rules. Conditional Formatting › Manage Rules › This Worksheet. Hundreds of rules? Delete and re-create a few.

5. A damaged file

File › Open › select the file › click the arrow on the Open button › Open and Repair.

Prevent it

File › Options › Save › AutoRecover every 5 minutes. Keep Excel updated (File › Account › Update Options).