If you’ve been plagued by networking problems since updating to OS X 10.10 Yosemite, your salvation may be at hand with the, which ditches the unreliable discoveryd service for the trusty old mDNSResponder. In plain English, that should mean the return of stable networking in OS X (see “ ,” 7 May 2015).
You can install 10.10.4 via Software Update, or from Apple Software Downloads as (1.09 GB) and  (2.02 GB) installers. As always, it’s smart to wait a few days to see if any major issues crop up, but if you’ve been nagged by networking problems, an immediate upgrade may be advisable. Be sure to back up first!
In the world of Photos, we’re hoping OS X 10.10.4 addresses the sync issues brought up by Adam Engst in “” (20 May 2015) and “ ” (19 June 2015). Apple mentions fixes like “improves reliability when syncing photos and videos to iCloud Photo Library,” and “improves the reliability of upgrading iPhoto and Aperture libraries to Photos.” Also, 10.10.4 fixes an issue that could cause Photos to crash after importing some Leica DNG files.
For enterprise customers, OS X 10.10.4 has a fix for an issue where Macs bound to directory services could stop responding under certain conditions. Also, the update grants the capability to create mobile accounts with the
createmobileaccount command-line tool and fixes an issue in Profile Manager that could allow users to install pre-release software even when the setting was disabled.
As always, OS X 10.10.4 also includes numerous.