The Conditional Formatting command is able to color all unlocked cells in a specific range in Excel. And you can do it as follows:

1. Select the specific range you want to highlight all unlocked cells.

2. Click the Home > Conditional Formatting > New Rule.

3. In the opening New Formatting Rule dialog box, you need:

(1) Click to select the Use a formula to determine which cells to format in the Select a Rule Type box;

(2) In the Format values where this formula is true box, enter the formula =CELL("protect",A1)=0 (A1 is the first cell of the selected range);

(3) Click the Format button.

4. Now you get into the Format Cells dialog box, click the Fill tab, specify a background color in the Background Color section, and click the OK button.

5. Click the OK button in the New Formatting Rule dialog box.

Then all unlocked cells in the specific range are highlighted with specific color at once. See screen shot below:

If you have installed Kutools for Excel, its Highlight Unlocked utility can help color all unlocked cells promptly in Excel.

1. Click the Enterprise > Worksheet Design to activate the Design tab.

2. Click Design > Highlight Unlocked. And now all unlocked cells in the whole workbook are highlighted at once. See screenshot:

Note: Even if your worksheet is protected, this utility can also highlighted all unlocked cells.