If you're planning to upgrade to OS X El Capitan and you use Outlook 2011 to get email from Microsoft Exchange, you may want to delay upgrading. On El Capitan, connecting to Exchange email servers causes Outlook 2011 to freeze and display a beachball cursor. Update 10-7-2015: Microsoft has released Microsoft Office for Mac 2011. Despite stating that no settings would be changed I have regular difficulty accessing the Outlook Server via OS x El Capitan on my iMac to gain access to my Hotmail Account since Microsoft updated Outlook. On some occasions I have been unable to gain access for four days.
Outlook Mac Os X El Capitan
If you're one of the users who upgraded OS X to El Capitan last week and are having issues with Outlook 2011, you're in luck: Microsoft has released a fix for the show-stopping bug affecting Outlook 2011 for Mac. The Microsoft KB article (KB 3098396) describes how the bug caused Outlook to hang whenever it attempted to sync online with email servers:
Outlook For El Capitan Download
Shortly after you start Microsoft Outlook for Mac 2011 on Mac OS X El Capitan (version 10.11), Outlook hangs when it tries to sync with the server. The Spinning Wait cursor is displayed, and the application status is displayed as 'Not Responding.'
The issue did not affect offline users, however this would obviously leave Outlook's functionality severely crippled. Thankfully the patch appears to resolve the issue and is much better than Microsoft's advice prior to this update, suggesting users roll back to OS X Yosemite.
Microsoft Outlook El Capitan
Despite Office for Mac 2011 receiving a patch, Office 2016 for Mac still has serious bugs itself including the apps crashing. Microsoft told MacRumors they are working on a fix:
Outlook 2016 Mac El Capitan
'We know that some users of Office 2016 for Mac are experiencing issues as a result of upgrading to Mac OS X 10.11 El Capitan. We are actively working with Apple towards resolution.'
Users can download the Office for Mac 2011 14.5.6 Update (113.4 MB) via Microsoft AutoUpdate or in a package at Microsoft Support.
Outlook Mac El Capitan
Source: Microsoft Support via MacRumors