Hi all, I wasn't able to find anything similar to the Yosemite threads yet, so I thought of posting this in case that rings any bells to anyone else: I've used all the incremental upgrades starting from latest 10.9 to 10.10 DP6 (that is, I've installed DP1 over Mavericks and then incrementally all the next ones, DP2, 3, 4, 5 & DP6). At some point (not sure exactly when) I've noticed the following odd issue that still persists. So here it is: The problem: When holding Option key during boot, the startup manager should be displayed. This is happening, but not before 2-3 minutes. If I don't hold the "Option" key, the OS X boots fine without any delays. I can confirm that this was not happening until recently. Troubleshooting so far: 1. Tried booting with "Option" key without any external drives connected. Delay remains the same. 2. Run the Apple h/w test. It completes successfully (although towards the end, it is stuck for several minutes - I don't know if this is normal or not since I didn't use it before on this machine). 3. Removed the third party memory just in case. No change. However, besides the huge delay, when the startup manager shows up, it works fine and boots everything as before (internal & external volumes). The only thing I've not tried yet, is to completely wipe the Yosemite and go back to 10.9 (since there are changes on EFI for each version of OS). The machine: Mac Pro late-2013, quad core, D700s, 512 SSD, 12GB RAM + 4GB from 3rd party vendor, Apple TBD monitor. Thanks for reading this. P.S. Taking the machine back to reseller (no official apple here) is the last solution for me.