Apple is still fighting to get rid of the DNS errors seen in recent versions of OS X 10.10 Yosemite, and as part of that battle it has ditched the buggy discoveryd service in its recent 10.10.4 beta, replacing it with mDNSResponder, which was last used in OS X 10.9 Mavericks.
With the OS X 10.10.4 beta, released on Tuesday, Apple reinstated mDNSResponder to handle DNS processes previously assigned to discoveryd since the debut of OS X 10.10 Yosemite.
The discoveryd process would fail to resolve device names, duplicate machine names and would cause other network problems that led to system slowdowns. other issues, such as consuming CPU resources, draining battery life, and Wi-Fi issues were also attributed to discoveryd.
While discoveryd was thought to be linked to Handoff functionality, AppleInsider reports those features appear to still operate properly, even with the return to mDNSResponder.
Users should note that the return of mDNSResponder could merely be a stopgap solution as Apple attempts to resolve issues with discoveryd. We’ll know for sure what Apple has planned when OS X 10.10.4 is released to the public.