MSR-UPL-2106 Failed to refresh file ... Incompatible columns detected.

[JBCLARK20]

Working in Cognos 11.x with a data module using excel uploads.
File A uploads every time with no issues.
File B fails to upload with the message MSR-UPL-2106 Failed to refresh file ... Incompatible columns detected.
Reviewing the file in excel I see no differences in data types between the old file B and the new file B. The file sizes are also about the same. I thought the sender may have changed the file structure, so I rebuilt the module using a new file B. The module built and ran, but the next day would not accept a new file B.

Are there best practices or hints for preventing the MSR-UPL-2106 error?
Running a file compare between the files does not show any differences.

[bus_pass_man]

This will get us started:

Are the column headers the same names as the original file?   Are they in a different order?  Have you added columns?

Is everything following the specifications of this doc?
http://www-01.ibm.com/support/docview.wss?uid=swg21974196

[JBCLARK20]

Thank you for the prompt reply.
The file matches the specifications on the link.
The file is a standard report output from a partner application.
The file columns are the same and have the same names. No new columns are added and none are taken away.
The file is a block of data, column headers and rows, no empty rows between records, no title rows, no summary rows.
The files are Microsoft Excel 2013 worksheets about 4M in size.

There are cases where the first several cells in a column may be blank. I'm wondering if Cognos only reads the first few records to determine the field type.
Would it be worthwhile to create a dummy record of data that loads and make it the first record of the load?

[rafmoles]

Not sure if this still remains an issue for you. I received the same message when attempting to update a previously uploaded file. Turns out that the updated spreadsheet contained an invalid date in a date column. Fixing the date in the spreadsheet allowed it to be successfully uploaded.