How to Restore All Hidden Columns in Excel

1. Open the spreadsheet in Excel.
2. Click on the arrow in the top left corner of the Excel spreadsheet. This highlights all data in the workbook.
3. Click 'Format' in the 'Cells' menu along the top of the page. A drop-down menu appears.
4. Click 'Hide Unhide' under the 'Visibility' heading, then click 'Unhide Columns.' Changes are applied instantly and all columns are visible.