Excel 2010 :: Error / Source Not Found With Certain XLSM Files

I am working with Excel 2010.

There are certain .xlsm files in our system (some have macros and others don't) which generate "Error: Source not Found" in the Edit Links dialog box when the Check Status button is pushed. However, the source location is correct, as you can click on Open Source and it will open the correct file.

For simplicity of explaining my issue, consider the following scenario. In my workbook "Corn Production Summary.xls_" I link to 2 source files: "Iowa.xlsm" and "Nebraska.xlsx" (Note: The extension of the summary file doesn't matter. This error happens regardless of what the summary is.)

When I open "Corn Production Summary" I am prompted to update values. I select Update and the file refreshes and recalculates appearing to have updated all values (i.e. no error messages). However, the values from Iowa.xlsm did NOT update and there was no error message indicating that the values didn't update.

To confirm this, I go to Data>Edit Links>Check Status in "Corn Production Summary" and I see that Iowa.xlsm has the "Error: Source not Found" error. I click on Open Source and once the file is open, my data in the summary file will update.

One work around was to do the following process (with the summary file closed):

1) Iowa.xlsm and Save As Iowa.xlsx (removing macros if needed)

2) Save As Iowa.xlsx as Iowa.xlsm (overwriting the file that is currently there and readding the macros)

3) Open the summary file and both Iowa and Nebraska work just fine now.

There are a lot of files like this, and because Excel doesn't prompt us that it isn't really getting the values from these certain .xlsm files we would have to search in "Edit Links" for each file to make sure that they really are updating.