This method will find all merged cells in the specified range with the Find and Replace feature, and then delete these merged cells. Please do as follows:

1. Select the range you will find out all merged cells, and open the Find and Replace dialog box by pressing the Ctrl + F keys simultaneously.
Note: You can also open the Find and Replace dialog box by clicking Home > Find & Select > Find.

2. In the opening Find and Replace dialog box, please click the Options button to expand the Find and replace options, and then click the Format button. See screenshot:

3. In the opening Find Format dialog box, go to the Alignment tab and only check the Merged Cells option, and then click the OK button. See screenshot:

4. Now you get back to the Find and Replace dialog box, please click the Find All button.

And then all merged cells are found out and listed at the bottom of the Find and Replace dialog box.

5. Select all of fount out merged cells in the Find and Replace dialog box, and then close the Find and Replace dialog box.

You can Select all merged cells by selecting one merged cell in the Find and Replace dialog box, and then pressing the Ctrl + A keys simultaneously.

6. Now all merged cells are selected in the specified range. Right click any merged cell, and select the Delete from the right-clicking menu. See screenshot:

7. In the popping up Delete dialog box, check the Shift cells left option or Shift cells up option as you need, and click the OK button.

8. A warning dialog box comes out as below screenshot shown. Just click the OK button to go ahead.

So far we have deleted all merged cells in the specified range. See screenshot:

This method will introduce Kutools for Excel’s Select Merged Cells utility to quickly select all merged cells from a specified range, and then delete them easily in Excel.

1. Select the range you will delete all merged cells, and click Kutools > Select > Select Merged Cells. See screenshot:

2. Now all merged cells are selected in the specified range, and a dialog box comes out to show how many merged cells are selected. Just click the OK button to close it.

3. Right click any merged cell, and select the Delete from the right-clicking menu. See screenshot:

4. In the popping up Delete dialog box, check the Shift cells left option or Shift cells up option as you need, and click the OK button.

So far all merged cells in the specified range are completely deleted.

Sometimes you may just need to unmerge or split merged cell from a specified range to erase merged cells. This section recommends Kutools for Excel’s Unmerged Cells utility to unmerge/split all merged cells with only one click.

Select the range you will split all merged cells, and click Kutools > Range > Unmerge Cell. And then all merged cells are unmerged immediately. See screenshot:

How to unmerge cells and fill with duplicate values in Excel?