"Excel found unreadable content in [Book_Name]" in Excel 2010 PowerPivot table containing KPIs and time dimension measures

When attempting to open in Excel 2010 an .xlsx doc containing two PowerPivot Tables I get an error message:

"Excel found unreadable content in 'Book_Name.' Do you want to recover the contents of this workbook?"

Upon clicking yes, Excel disables one of the first PowerPivot tables (which also contains KPIs) and transforms the data into text and I get the below error log:

<?xml version="1.0" encoding="UTF-8" standalone="true"?>
-<recoveryLog xmlns="error095920_01.xmlErrors">http://schemas.openxmlformats.org/spreadsheetml/2006/main"><logFileName>error095920_01.xml</logFileName><summary>Errors were detected in file 'C:\Users\xxx\Desktop\Powerpivot Demand Supply Model 3i.xlsx'</summary>-<removedParts summary="Following is a list of removed parts:"><removedPart>Removed Part: /xl/pivotTables/pivotTable1.xml part with XML error. (PivotTable view) Catastrophic failure Line 2, column 0.</removedPart></removedParts>-<removedRecords summary="Following is a list of removed records:"><removedRecord>Removed Records: Workbook properties from /xl/workbook.xml part (Workbook)</removedRecord></removedRecords></recoveryLog>

I've already tried:

• Reinstalling VB for Apps
• 2010 Hotfix package (already had it)

Could this have something to do with the PowerPivot KPIs? Are KPIs unstable in general and should I be avoiding them? There are time dimension calculated measures in that table.