Hi folks,
Similar issues here plus what I hope is a useful observation. I’ve typed this out in detail as I’ll be sending it to Apple support, but others may be interested.
For the record and to help the troubleshooters, I’m using a new MBA (mid-2013 model, OSX 10.8.5, 2xUSB3 slots) purchased early January 2014, and a new 1 TB Seagate Backup Plus portable drive (USB3) purchased Feb 2014. I’ve reformatted the Seagate drive (let’s call it S1TB) via Disk Utility to create 3 new partitions: 2x Mac OS Extended Journaled, incl one for Time Machine, and 1x FAT32 for bringing files over from my old Dell laptop.
Typically I get the “disk not ejected properly” (DNEP) message after a period of inactivity on the MBA and when the S1TB isn’t active with a task, like a Time Machine backup. I don’t recall having this problem while S1TB is working: only when it has nothing to do and takes a snooze. Within a minute of the MBA display switching off, the light on S1TB also goes off. I assume it’s gone into some kind of power-saving or sleep mode, despite the fact that, as I understand it, Seagate drives take their cue for sleep from OSX on Mac computers and I have “Put hard disks to sleep when possible” de-selected in Energy Saver on both battery and power modes. Not sure why that is happening. http://knowledge.seagate.com/articles/en_US/FAQ/208571en
After tapping the space bar or track pad to bring the MBA display back, the DNEP message will nearly always appear immediately and the S1TB will have disappeared out of the devices list in the Finder sidebar (if it is the visible window). Occasionally the Finder window will spontaneously close. Occasionally, too, the DNEP message doesn’t appear immediately and S1TB doesn’t disappear from Finder immediately, but clicking on S1TB in the device list will trigger the message.
I’ve tried Robin’s solution (see post on 25 Jan 2014) but it didn’t work for me. BTW Robin, when you say “pull this folder onto the desktop”, I presume you effectively mean delete the System Config folder so it is re-created on the re-boot? This is what I did several times but no success (…and I noticed that the re-boot re-sets the sleep settings in Energy Saver to factory/default settings. I had de-selected “Put hard disks to sleep when possible” on both battery and power modes, but this procedure sends them back to factory/default.)
Following an inconclusive call with an Apple support rep, I did some comparison of the performance of my S1TB and an older USB2 Seagate 250 GB (I’ll call this S250). I connected both drives to the MBA simultaneously, one in each USB slot and let the computer run until the display sleeps. I then bring the display back by tapping the space bar. I ran this same test with the drives connected to the opposite slots on the MBA, and both before and after Robin’s recommended solution.
In a nutshell the S1TB was spat out every time with the DNEP message. On the other hand, the S250 on USB2 seemed bulletproof. No DNEP messages ever. Not even after closing the lid and forcing the MBA to sleep, and not even when I had to pull the S250 out while it was still listed in Disk Utility and, apparently, still spinning. (For some reason I couldn’t eject the S250 in disk Utility, but that seems like another story.) For what it’s worth USB2 FAT32 thumb drives don’t cause DNEP either (occasional problem with initial recognition but that’s another other story).
Conclusions: This could be a problem with the S1TB model or my particular S1TB drive but the fact that it works without fail on my Dell laptop seems to rule this out (…although the Dell is a USB2 machine). Alternatively, maybe there’s a USB3 handling problem on Mac’s? ie. too sensitive or too fast in responding to the sleep status of external drives?? This would need some additional testing (eg. my S1TB connected to another MBA; different USB3 portable drives connected to my MBA). However, I see other comments seem to suggest the problem may be with USB3 or that USB2 drives/connections don’t have the DNEP message problem (see post by Mark on 1 Feb 2014, Linda on 30 Jan), so maybe this is worth further investigation.
I’m guessing it would mean the only effective fix will come via an update from Apple. Kind of ironic after shifting from windows because of all of its alleged shortcomings!
Peter
By the way, it would help Apple and others if everyone listed the possible variables here: eg. Mac model, OSX version, USB slot version, external drive model and usb version, external drive re-formatted on not, situation in which DNEP appears, etc. So, to practice what I preach, and in response to other suggested causes mentioned in this and other DNEP-related posts: Mavericks – I’m still on 10.8.5 but getting the DNEP message anyway (…and I won’t be upgrading for the moment); Migration Assistant - I used this when I started transferring files from my old Dell laptop but only as a trial. I think I only selected and migrated files on my desktop for migration. Seemed like it was going to be a time-consuming process so I transferred the rest of my files (successfully) via the S1TB; Faulty cables and ports – Seems unlikely given that both products are very new, S1TB works on the Dell laptop, and the results of testing on both MBA ports described above.
