Can't make my drives spin down properly

[krisventure]

Hi! I've registered to this site just for this question which has been bugging me for many months and I've tried following most of the advises I've found.
My external drive doesn't spin down properly when I eject it. Specifically, it spins down when I eject it but then a second later it's back spinning again, even though I can't see it in Finder any more.
I've even bought a new hard drive of a different brand (before it was Sony, now it's LaCie Porsche design 2TB from the Apple store) and have the exact same issue. What's worse, it used to work, the ejection and spinning down before, and then one day it didn't work any more and started to show these symptoms and now it won't work with my new drive either. But it does work with another drive (an old WD My Passport), but then again, it doesn't work with the 2nd device of the exact same model (my other old WD My Passport). So it seems to be totally random as far as drive models are concerned.

What I've tried:
1. Removed it from Spotlight indexing
2. Removed it from my antivirus (Bitdefender) monitoring path.
3. Used sudo fs_usage | grep /Volumes/<myVolume> command and only SystemUIServ seemed to show 'getattrlist', 'fsgetpath', and 'statfs64' every couple of minutes, but nothing shown after ejection.
4. Used sudo lsof | grep SystemUIServ and got this (No idea what to make out of it):
authd 134 root 21r REG 1,4 464336 17835101 /System/Library/CoreServices/SystemUIServer.app/Contents/MacOS/SystemUIServer

SystemUIS 3691 user txt REG 1,4 464336 17835101 /System/Library/CoreServices/SystemUIServer.app/Contents/MacOS/SystemUIServer

SystemUIS 3691 user txt REG 1,4 12490 5891393 /System/Library/CoreServices/SystemUIServer.app/Contents/Resources/menuitemNormal.pdf

Any help would be appreciated as I can hear the little error beep when I forcibly unplug right now while it's still spinning and I'm very concerned that it'll one day damage my backed up data.

 

[chscag]

There's probably something running in the background that queries the hard drive frequently and that might be why it spins up again. Some suggestions: First ditch Bitdefender AV as it's not needed anyway. Try restarting your Mac (which you haven't told us anything about) in safe mode and go thru the motions of ejecting the drive to see if it ejects properly or not.

 

[krisventure]

Hi and thanks for getting back to me. Yes it does spin down normally in safe mode. But how should I proceed with the investigation of background processes which may wake up the drive? I thought I'd figure it out with fs_usage and lsof but I'm not sure what to look for as those commands only showed anything before ejection so they won't tell me what happens when it's spinning afterwards.

 

[chscag]

Probably the easiest way is to keep your Activity Monitor app open and watch it as you eject the drive and then it spins up again. You might have to do it several times to spot what's going on as sometimes the Activity Monitor display can be overwhelming. The reason safe mode worked is because in safe mode all third party kexts (drivers) are suppressed and only Apple kexts are allowed. It also stops all third party startup apps.