Excel Workbook Errors

We have an Excel workbook with a number of tabs, formulas and protected areas. We save in Excel 2013 as .xlsx or stcrict OO .xlsx. When we open in LibreOffice (our field users) and enter numbers into unprotected cells and save as Excel 2007/2010/2013 .xlsx or Open Office .xlsx. We then get the error below when opening in Excel 2013.

Repaired Records: String properties from /xl/sharedStrings.xml part (Strings)

How do we determine where in the Excel sheet the problem lies?

Jim

officeotron, https://code.google.com/p/officeotron/, offers vaildation of OOXML documents. If LibreOffice is writing invalid files, I think a bug report would be in order. If Excel is complaining about valid files, the LibreOffice folk might (or might not) be willing to implement a workaround.

Meanwhile, can you avoid the error message by using, for example, an ODF file?