Internal Hard Drives disappearing from Yosemite Desktop

Today I updated a MacPro from OS 10.8.5 to OS X 10.10.5. The computer is used primarily for editing audio & video and has a Samsung SSD for the OS & Apps and three drives in the other bays for everything else.

Since the upgrade today, whenever I restart the computer, the HD's in the other three bays no longer appear on the desktop. They cannot be seen by Disk Utility nor do they appear in the System Report.

If I do a hard SHUT DOWN & restart, they appear again.

The Finder preferences are set to show everything (internal/external drives, etc.)

Are there any prefs I need to trash or a setting I'm forgetting? All 4 drives have only been in service since Sept. of this year, and I've had no problems with them under OS X 10.8.5.

I'm going to run EtreCheck, but thought I would get the ball rolling & see if this is a common issue with a simple fix!

Thanks!