I'm having major issues with my Promise Pegasus R4 running on Yosemite 10.10.5 and Promise Utility Firmware Version 3.18.0000.36.
When I first boot up the OS X sees the R4 just fine, I can get in and look at clips via Finder, tag, rename, etc. After minutes, maybe 15 mins, it's no longer happy. Finder begins to freeze, spin, hang forever, and where I usually can (as I do on any other drive, and previously on my R4) view clips, do a two-finger touchpad scrub through them in a Finder window, here it will freeze before I can even see the clip's video image, it will not show the video and immediately produces the 'ole beach ball. This ONLY happens on my Pegasus, no other drives.
I originally treated this as an OSX 10.10.5 issue. I trashed Finder and Sidebar (as I thought initially it could have something to do with high volume of tags) plists, but none of this seems to have anything to do with it.
The R4 is cleanly formatted RAID 5 (12TB usable, with only 4TB of media on it).
Please, Promise, Wise Users, anyone, this is an SOS. Any help would be sooo appreciated. I really need my Promise Pegasus R4 to play well with others so that I can finish my job. As it is I cannot access my work.