Since the data in the external document may change, it is recommended to periodically update the reference to this data in the current document.
To update the references after opening the current document, click Refresh data in the notification banner “Linked documents might have changed. Refresh this document to get the latest data.”.

The application will recalculate formulas and functions taking into account new values from an external document.
If the document is not available, the notification banner “Linked documents are unavailable. The spreadsheet uses the last saved data." Click Close in this banner.

To update the data when working with a document, do one of the following:
–On the Data tab, click
Refresh data.
–When working in macOS, select the Data > Refresh data command from the command menu.
–Press Ctrl+Shift+F5(Windows, Linux) or ⇧Shift+⌘Cmd+F5(macOS).
External reference data is updated automatically when a new reference to a document is created or when an existing one is edited. In this case, only the data for the documents specified in the created or modified formula is updated.
Error #REF! displayed in cells if:
–When creating a reference, the external document specified in the reference is unavailable (or the specified sheet does not exist in it), and there are no previously saved values for it.
–When uploading a document, there are no saved values for the external document specified in the reference (the data was not received when creating the reference).