You had customized Excel Ribbon previously and later you want to restore it to its original state. To reset Excel Ribbon to its original state, follow these steps.
Step 1 - Right-click anywhere on Excel Ribbon and then select "Customize the Ribbon", as shown in below image.
"Excel Options" window is opened and its "Customize Ribbon" Panel is displayed as shown below.
"Excel Options" window to customize Excel Ribbon can be opened by following methods also.
• Click the "File" tab in Excel Ribbon and then click "Options". Select "Customize Ribbon" Panel.
• Right-click anywhere on the "Quick Access Toolbar" (except on "Customize Quick Access Toolbar" drop-down button). Click "Customize Ribbon".
Step 2 - Click on the down arrow in "Reset" customizations split button, as shown below.
You can see from the above image that there are two options.
1) "Reset only selected Ribbon tab" - If you select this option, you can reset select tabs to their original state. You can reset only inbuilt tabs to their original state if you select this option. You cannot reset any custom Tabs you had created.
You can see in above image "Reset only selected Ribbon tab" is greyed out (disabled). "Reset only selected Ribbon tab" is greyed out (disabled) because no customization is made in Excel inbuilt Tabs (nothing to reset).
2) "Reset all customizations" - If you select this option, you can reset all tabs on Excel Ribbon. Selecting this option will reset Excel Quick Access Toolbar also. Any custom Tab you had created before will be removed.
Step 3 - Select the option you required and click "OK" to reset Excel Ribbon.