How to resolve issue Power Pivot ribbon disappears in Excel 2013?

If you are new to Power Pivot 2013, the most frustration is Power Pivot ribbon frequently disappears in Excel 2013. In some cases, the Power Pivot ribbon will disappear from the menu if Excel determines that the add-in is destabilizing to Excel. It might occur if Excel closes unexpectedly while the Power Pivot window is open. 

To restore the Power Pivot menu, you might do the following three steps in order:

1. Close running Microsoft Excel process

• Go to Task Manager
• Right click Microsoft Excel and “End task”
• Open Excel again and verify Power Pivot ribbon

2. If this is not working, verify Add-Ins installed

• Go to File > Options > Add-Ins.
• In the Manage box, click Disabled Items > Go.
• Select Microsoft Office Power Pivot in Microsoft Excel 2013 and then click Enable.

3. If the previous two steps do not restore the Power Pivot ribbon, or if the ribbon disappears when you close and reopen Excel, try the following:

• Close Excel.
• Point to Start > Run and then type regedit.
• In Registry Editor, expand HKEY_CURRENT_USER > Software > Microsoft > Office > 15.0 > User Settings.
• Right-click PowerPivotExcelAddin and then click Delete.
• Scroll back up to the top of Registry Editor.
• Expand HKEY_CURRENT_USER > Software > Microsoft > Office > Excel > Addins.
• Right-click PowerPivotExcelClientAddIn.NativeEntry.1 and then click Delete.
• Close Registry Editor.
• Open Excel.
• Enable the add-in using the steps at the top of this article.

These three steps should resolve most of the Power Pivot ribbon missing issue.