OS X El Capitan - Early Issues

So it’s only been a few weeks since the release of Apple’s latest and greatest operating system release, “El Capitan”, representing OS X version 10.11. Unfortunately for us and many of our clients, the initial release includes several show-stopping bugs with Mail, Address Book and Calendar.


We’ve had reports and experienced first hand an issue in Apple Mail where within minutes after opening it will quickly consume all physical memory (RAM) on a computer until all other programs are starved and the system grinds to a crawl.

Apple Support Communities thread

Address Book & Calendar

Several of our clients who updated to El Capitan had issues where CalDAV and CardDAV accounts that had previously worked suddenly could not connect. The workaround we have found is to configure the account without SSL encryption, which is not recommended for security reasons.

Apple Support Communities thread / Apple Stackexchange Question

FileMaker Pro

Not as serious but FileMaker released an advisory that users of FileMaker 14 and below should not update to El Capitan due to user interface bugs and some instability. This is now resolved with update 14.0.3, available for download now.

In summary, unless you have an urgent need to, please do not upgrade to El Capitan if you rely on these applications working, until Apple have resolved the issues above.