After upgrading from 1.9.5+ to 1.9.12+ (which went flawlessly), we can no longer export quiz results to Excel format. Regardless of the portion (Overview, Item analysis or Detailed Reponses – an additional report added but has been tested with and without this additional report), the Download in Excel format produces a file that Excel can't understand.

When trying to open the produced file, Excel complains that the file is in a different format than specified by the file extension (.xls). Choosing to open the file anyway displays garbage in the file. It appears like part of it is font specifications and sometimes part of the data is recognizable but buried amongst a lot of other characters. A screen shot is attached. BTW, this also appears to affect the ODS export. However, I can use the Export to Excel feature in the gradebook and that works as expected, in case that matters.

This seems like it's similiar to other bugs that dealt with UTF8 encoding, but our database has been UTF8 the entire time and everything was working in 1.9.5+. And any of the solutions found for those other bugs were already incorporated into 1.9.12 so I'm stumped.

Any help/advice would be appreciated.