Anyone else having problems with external disks unmounting randomly/suddenly on Mavericks?

Just found this thread, but have been seeing this problem for a few months.

2008 iMac, Snow Leopard (clean install), minimal peripherals, short cables, no wireless anything. No weird 3rd-party software. No gaming.

The only atypical items I have are a new Wacom tablet, and a newly-installed Samsung internal SSD.

Never owned a WD drive of any kind; OWC ext HDDs are typically Hitachi. All HDDs are set up as single-partition.

Did the PRAM and SMC after problem was several weeks old, per OWC's direction.

Unmounting problem started after adding an OWC Qx2 4x2TB enclosure, configured as JBOD via FW800. Not only unmounting, but inability to perform other (seemingly unrelated) tasks, and goofy Sleep / Restart / Shut Down behaviors. Many error messages (mostly "-50"). Simply put, when the Qx2 was removed, and replaced with a single ext HDD (also OWC), no issues. I finally got an RMA replacement from OWC, and overall everything works MUCH better, BUT – the unmounting did resume, although only twice (yesterday and today) since last week's reinstall.

I don't believe files are corrupted, but can't really know that until I encounter one.

To me it doesn't seem like OSX, but I'm not remotely an expert. But after discussing this with the tech who installed the internal SSD, and the fact that a replacement enclosure works much better (the same 4 Hitachi drives have been retained throughout), I wonder if there is some finicky power supply and/or voltage spec that is causing intermittent failure to recognize. Something that could be fixed with firmware on Apple's part?

Just adding to the pile.

Thanks for this thread. Will take a look at some of the recent suggestions.

Similar issue.

Dual monitors go blank for a moment then unmount all ten drives at the same time.

The whole machine then lagged until a forced shutdown and restart is required.

Very odd indeed. Can't figure out how to stop them unmounting.

I have a brand new mac pro... this shouldn't be an issue at all.

Come on apple. get with it already! This just started happening.

I agree about it being some kind of freaky power thing that's causing the dismounting. I tried hooking my HD up to my computer without any other peripherals connected. Worked well and didn't dismount, even when my computer went to sleep it didn't dismount by itself. I then tried it a few times after, with all my stuff connected i.e.; keyboard, monitor and it worked for a few times perfectly. Now, it started to dismount again. I think the power is fluctuating to cause this. fyi.. my disk has 3 partitions and the one for time machine is encrypted. Never had a problem before. All started out of the clear blue like everyone else here.

APPLE!! DO YOU HEAR US?!!! Fix the problem please!!!!

Came across this in another thread. Particularly for the WD drive that I have. Read before installing. http://www.macupdate.com/app/mac/31158/keep-drive-spinning

I'm going to try it since I already tried the system preference thing and it didn't work per the note in this link. Person in the other thread said he hasn't had a problem since installing this. I'll keep you posted.

I have the solution for all the problems above.

go to system preferences-> Spotlight-> Privacy-> + (add the drive or drives that are presenting issues)

Fixed!

This worked! You're a genius! Thanks.

go to system preferences-> Spotlight-> Privacy-> + (add the drive or drives that are presenting issues)

Fixed!

Genius. Have had this same problem for more than a year, on both a Mini 2012 and iMac Retina 2015. Happened in Mavericks, Yosemite, and El Capitan.

Never found a solution, until this.

Thanks.

Needs to be publicized for the entire Mac community.