When attempting to export a course gradebook to an Excel spreadsheet, we receive a deadlock error almost immediately after the export is started. This impacts some courses, but not all, so unfortunately I do not have a good way to replicate the error. Exports to OpenDocument spreadsheet and Plain text file both work properly in the impacted courses. This seems to be the same problem reported in MDL-51603. Our current environment is:
Moodle 3.1.3
Windows Server 2012R2
MS SQLServer 2014
PHP 5.6