Workbook won't display after macro is complete (works just fine in Excel 2010, 2007)

Hi all,
We are transitioning to Office 2013 and in the process I have noticed a macro is not working as expected like it did in Office 2010.

The Process:
A user exports an SSRS (SQL Server Reporting Services) report into Excel, then they click a link within the report that opens the macro file with that launches itself via the Auto_Open function. The macro finds the exported SSRS report and begins its work. When complete the user is prompted to close the macro file. Typically the final report is displayed and the user can continue their work. We have been using this method for 2 years now with no issues in Office 2010 or 2007.

While processing I keep the user informed of the macro progress by posting updates on a specific macro tab.

The Problem(s) only in Excel 2013:

1. The updates I am providing the user do not show up. just a blank Excel window.
2. The final product, the modified SSRS report, is not displayed after the user closes the macro file. I know the completed file exists and I can see it in the Project window if I have the Developer window open.

I'm sure these two issues are related.

I always use the Aplication.ScreenUpdating = False at the beginning of my macros, and Application.ScreenUpdating = True at the end to help speed the processing of my macros. I have noticed that if I disable this (remark it out) that the problem still persists, AND the screen will still not update while the macro is processing.

I have extensive VBA expierence and this issue is quite baffeling. Like I said, this macro works perfectly in Excel 2007 and 2010.

Any help at all would be greatly appriciated.