Randomly ejecting USB hard disks

After almost a week another disconnect. After some experimenting I suspect the cable to the problem disk is a bit crappy. E.g. it took a while before the system recognized I reconnected the disk or it did not find it at all, or only after numerous attempts. When I replaced the cable response was immediate. So its worthwhile trying these kind of thing if you have the problem.

I'm getting spontaneous auto ejects both while the computer is asleep and sometimes when awake but idle. I only get this when the external is connected via Thunderbolt 1, not USB3, that's stable.

Mac = Mac mini

OS = 10.9.5

Drive = LaCie 2big, 8TB (bought Sept 2014)

Thats good to know that it is somewhat stable.l my lacie drives are older, so I dont have thunderbolt for them, but they are too old for usb3. Usb2 should be fine, but apparently not because of my random ejects. I might just have to bite the bullet and just get a much newer lacie drive. If it still boots Apple is going to hear some choice words from me. :/ i apologize for the typos. Ironically my ipad is not letting me select my errors to change. On that note, my current problem (since I gave up on the drives) is that my IMAC will randomly restart. And it happens to people often enough that it is called a sleep wake error. How Apple is still in business is really beyond me.

I ended up permanently disconnecting one WD My Passport USB 3.0 drive, that would occasionally disconnect or hangup the complete system. The remaining drives (both USB 3.0 and Thunderbolt) are running fine. So I wonder if it really is a Mavericks problem or just bad hardware.

Im running a 4 year old Mac Mini with OS 10.6.8

Drive 1 Vantec 200GB

Drive 2 WD 1 terrabyte

Drive 3 WE 1 terrabyte

Drive 4 Seagate 1 terrabyte

Drive 5 Seagate 3 terrabyte

All has been running fine and I dont usually turn my mac off and its never in sleep mode and I dont use Time machine. The last drive was added a year ago and all has been running fine. Lately the drives all dismount at the same time and then remount by themselves. Drive 4 will not mount the Mac. Drive 1 stopped with message to initialize. Drive 2 and Drive 3 stopped mounting. All this within the last 2 weeks. Drive 5 still works fine, but it still dismounts and remounts by itself with the message box about dismounting drive improperly. All the drives are connected to the mini by D-Link hub model DUB-H7. Can Hubs wear out? For all the drives to dismount at the same time has to be a connection of the hub or a USB problem with the Mac.

Just purchased a WD 1TB My PAssport for Mac

Have a macbook mac os x 10.6.8

recently broke my older passport which was working perfectly fine then naturally purchased the new passport from WD. Spontaneously will eject immediately upon inserting into usb port?

Dont know what to try been reading the thread changing energy settings, calling WD and getting a replacement, and calling apple. Nothing seems to work.

Any ideas would help?

Thanks

Does the new drive have the same USB as the old one (USB 2 or USB 3)

You are running a pretty old version of OSX. If the new drive is USB 3.0 (which I assume) there might be a problem with your OSX version supporting that

thanks for the suggestion the old usb seems to be working fine now.