This message appears when one the following conditions occur:
A mismatched range of cells is being pasted into a merged cell. For example, if you merge eight cells and then try to paste a range of six cells into the merged cell, the alert appears. To fix this problem, copy and paste a range of cells that matches the size of the merged cell.
Cut or delete a row or column that includes a merged cell.
Clear the contents of a row or column that includes a merged cell.
Apply a filter to a column containing a merged cell, and then try to delete the merged cell.
To fix problems with cutting or deleting, split the merged cell and repeat the cut, delete, or clear operation. To split merged cells:
Locate and select the merged cell.
On the Home tab, in the Alignment group, click Merge and Center.
Note When splitting a merged cell, Microsoft Office Excel writes