This message appears when the maximum memory or file size limit for a Data Model is exceeded. In the 32-bit version of Office, the maximum files size for a workbook containing a Data Model is 2 GB, and the maximum memory that can be consumed by a workbook is 4 GB. If you exceed either of these limits, the workbook cannot be saved.
If this occurs, you must reduce the number of tables, rows, or columns that are linked, imported, or copied to the Power Pivot window before you can save the workbook. There are two ways to do this:
Delete any tables you don’t need. Delete them from the Power Pivot window. See Start Power Pivot in Microsoft Excel add-in to open the window.
Re-import data, setting filters to reduce the number of rows added to the data model. To avoid confusion in the data model, delete existing table before re-importing them. You will need to manually create relationships to establish connections in the model. See Create a relationship between two tables or Create relationships in Diagram View for more information.
Filtering data that has already been imported (as described in Filter Data in DAX Formulas) is not a solution for this error. Filtering imported data only affects how data is displayed.