Apple replaces buggy discoveryd service in latest beta of OS X 10.10.4
In the latest beta of OS X 10.10.4, Apple replaced Yosemite discoveryd, a daemon that searches for network resources, with an older, similar component. Yosemite users complained of several network issues due to the buggy discoveryd service.
According to some OS X Yosemite users, discoveryd causes, among other things, dropped Wi-Fi connections and network shares that appear in lists more than once. This would be due to bugs in discoveryd’s code. Some users therefore deliberately switched to discoveryd’s predecessor, mdnsresponder. This would make the aforementioned network problems disappear like snow in the sun.
After a number of less successful updates to OS X, Apple seems to be convinced of the persistence of the problems, 9to5mac reports. In the latest build of OS X 10.10.4, discoveryd has been replaced by mdnsresponder by default. It’s unclear whether Apple will add the problematic service to OS X in the future once the teething problems have been removed, or whether mdnsresponder will once again become a standard part of OS X Yosemite.