I would like to update to 10.10.4 to enable trim support on my SSD. I participated in the Yosemite Beta programme. Currently my Mac is on Beta 4. In Terminal, sw_vers reports ProductVersion 10.10 buildVersion 14A379b Within the AppStore, I have (for many months) had an update to Beta 5 showing as available but it neither downloads nor is installable. I have tried restarting my Mac into the Recovery Partition and reinstalling OS X. That takes me to ProductVersion 10.10 buildVersion 14A379b. I have tried disabling the 'install beta version' option within System Preferences/App Store. This simply removes Beta 5 visibility from the App Store. I have downloaded each incremental 10.10.x .dmg from Apple Support to try installing these individually in sequence. These simply report that the target volume is not in a state to accept the installation. Help! (I posted this at the Apple support forum and the post was immediately removed as it was regarded by the forum police as a question about beta software which I would contend it's not but hey, what do I know other than having an ability to read grrrrr!). Thanks in anticipation. BD.