When Excel shows Unprotected formula (often with a green triangle in the cell), it’s warning you that a cell contains a formula that can be edited or overwritten. This is part of Excel’s background error checking. The specific rule is typically Unlocked cells containing formulas.
What the message means
By default, all cells are locked to protect them from accidental or unauthorized changes. In this case, the cell containing the formula is not locked for protection.
Resolutions
Option 1: Protect the formula from being changed (recommended)
Use this option if you share the workbook or want to prevent accidental edits.
Step 1: Lock the cells people shouldn't edit (optional)
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Select the formula cells (the ones users shouldn't change).
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Select Format Cells (either select Format > Format Cells or use Ctrl+1 (Windows) or Cmd+1 (Mac) to open the menu).
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Select the Protection tab.
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Select Locked, and then select OK.
Note: By default, all cells are locked, but locking only takes effect after you protect the sheet.
Step 2: Protect the worksheet
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Go to Review > Protect Sheet.
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(Optional) Enter a password.
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Choose what users are allowed to do, and then select OK.
After the sheet is protected, formulas left in locked cells won’t trigger the Unprotected formula warning.
For more information about how to protect a workbook, see Protect a worksheet.
Option 2: Keep the sheet unprotected and stop seeing the warning
Use this option if you want formulas to remain editable but not have Excel flag them.
Ignore the warning for selected cells
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Select the cell (or select a range of cells) that shows the green triangle.
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Select the warning icon next to the cell.
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Select Ignore Error.
Tip: To do many at once, select the entire range (or use Ctrl+A to select the sheet), then choose Ignore Error.
Turn off the rule (“Unlocked cells containing formulas”)
This stops Excel from flagging this issue in your workbook.
Excel for Windows
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Select File > Options.
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Select Formulas.
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Under Error Checking Rules, clear Unlocked cells containing formulas.
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Select OK.
Excel for Mac
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Select Excel > Preferences.
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Select Error Checking.
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Clear Unlocked cells containing formulas.
Important: Turning off this rule doesn’t change your formulas or results—it only stops the warning.
Turn off background error checking (not recommended)
If you want to stop all green-triangle checks:
Windows: File > Options > Formulas > clear Enable background error checking.
Mac: Excel > Preferences > Error Checking > turn off background error checking.
For more information about how to control error checking, see Detect errors in formulas in Excel.
