I am having this problem and thus cannot control the sync on 2 macs. The following is from an imac running OSX 10.10.4 Following this advice from @Romanz 1) Make sure you use 2.0.120. It contains a fix for possible extension crash. LW>>>Sync 2.0128 2) If it does not help, open the OS X preferences -> Extensions -> Finder. Make sure that Sync extension is enabled. As a test, try disabling other extensions. LW>>> Google Drive extensions appear then disappear from Finder when toggling options in preferences. 3) If it does not help, open Console (don't confuse with Terminal window!), keep it open. Try unchecking, then checking Sync Finder extension in preferences (same place as described in #2). Send me the output that appears in console when you enable / disable Sync extension. LW>>> see below Output 16/07/2015 15:22:11.632 com.apple.preferences.extensions.remoteservice[836]: ### com.bittorrent.Sync.FinderExtension setting enabled:0 16/07/2015 15:22:15.700 com.apple.preferences.extensions.remoteservice[836]: ### com.bittorrent.Sync.FinderExtension setting enabled:1 16/07/2015 15:22:15.767 pkd[294]: enabling pid=282 for plug-in com.bittorrent.Sync.FinderExtension(1) FA0DD562-7228-40A8-9BB8-AA888861820C /Applications/BitTorrent Sync.app/Contents/PlugIns/FinderExtension.appex 16/07/2015 15:22:15.814 FinderExtension[859]: Currently watching: { "/Users/xxxx/BitTorrent Sync/Shared" = { FeIsReadWriteKeyName = 1; FeIsSelectiveKeyName = 0; }; } 16/07/2015 15:22:15.815 FinderExtension[859]: Version: 2.0.128