If you make changes to the source data a PivotTable is based on, the PivotTable isn’t automatically updated. Instead, you must manually refresh the PivotTable anytime you change its underlying source data.
You can also have Excel refresh the PivotTables in a workbook when a file opens
Click the PivotTable button on the Analyze tab.
The PivotTable Options dialog box displays. In addition to setting the PivotTable to refresh when opened, there are also various options here for PivotTable settings, such as assigning a name; changing the layout, format, and display settings; and adding alt text.
Click the Data tab.
Check the Refresh data when opening the file check box.
Now any PivotTables in the workbook will automatically refresh each time you open the file.