Following up on repeated complaints by developers regarding poor networking performance on OS X Yosemite, Apple has finally replaced ‘discoveryd’ in the latest beta of OS X 10.10.4 with the old mDNSResponder process to fix the DNS issues plaguing the latest version its desktop operating system. According to 9to5Mac, the change should address many of the network stability issues introduced with Yosemite’s new networking stack.
“The discoveryd process has been subject to much criticism in recent months as it causes users to regularly drop WiFi access and causes network shares to list many times over, due to bugs. Many developers, such as Craig Hockenberry, have complained about the buggy software and workarounds have been found to include substituting the older system (called mDNSResponder) back into Yosemite”.
Users have been reporting frequently that discoveryd would cause random crashes, duplicate names on the network and many other WiFi related bugs. In the latest beta however, looking at Activity Monitor, one can notice that discoveryd is no longer loaded by the system, and instead it now relies on the old mDNSResponder process.
While it remains unclear why Apple made the change in the networking stack in the first place since the old process worked quite well, it is being speculated that the new stack may be related to AirDrop and Handoff functionality, though both features work perfectly with the old process as well.