Scattered reports on the longest thread were encouraging.

'If you are using El Capitan, please update to 10.11.1 that Apple released today,' added Sunder Raman, also with Microsoft, on another discussion thread.

'Hello Everyone, Apple released the latest version of El Capitan this morning (10.11.1), please ensure that you are running the latest version of Office (15.15) and El Capitan (10.11.1),' wrote Faisal Jeelani, a member of the Outlook for Mac team, on one thread today. Today, a pair of Microsoft product managers simply urged users to update El Capitan to 10.11.1, without admitting blame or pointing fingers.

As time went on, however, Microsoft pointed to Apple as responsible, saying last week - after releasing an update to Office for Mac 2016 - that, 'We are actively working with Apple to ensure resolution with the next update of OS X 10.11 El Capitan.' Although most users blamed Microsoft for the screw-up, neither Microsoft nor Apple acknowledged fault.