Discussion regarding un-unmountable external drives and more..

Question

I have a Mac OS Extended (Journaled) formatted LaCie 2TB external USB 2.0 hard drive which I use for backup and file storage with my MBP running snow leopard. Some times when working extremely large folders at work, I actually work right of the hard drive and it works very well. But I have observed an increasingly annoying problem.
If I keep the drive active and working with whatever for a while and then decide to eject the disk, this almost always causes headaches. Either I get these warnings that the disk cannot be ejected because; Mail is using the drive, Safari is using the drive, Itunes is using the drive...... or some other app. This is annoying but can usually be resolved by simply quitting these apps. My question is; why does this occur? I see no reason for these applications to be using the disk? I haven't found a conclusive response to this question anywhere, always different suggestions/ideas/solutions? Does someone actually know what is causing this behavior and if it can be resolved "permanently"?
On the occasional time, quitting the applications suggested to use the drive doesn't allow me to eject the disc. It is still in use, but no apps are listed and the only way to eject is forcefully. I have tried:
sudo lsof | grep -i <filename>
And yes, I had some interesting results. Although spotlight is not indicating indexing in progress i see that spotlight is using the drive. I know you can add the drive under privacy in spotlight preferences and this eliminates this issue. But there is also "keychain access" using some file on the drive? I just cannot see why this would happen? When this happens, there is no way to safely remove the drive. I have tried relaunching finder, both through dock (ctrloptionmouse click) and terminal (killall Finder), but this does not resolve the eject issue. I have also tried stoping and relaunching SystemUIServer which was suggested somewhere, but this did not resolve the issue. Neither did umount volume or hdiutil eject /Volumes/GusExt/, it only works with -force which I would like to avoid.
Why would anything BUT spotlight use anything on the hard drive? And is there a way to safely kill any and every process using the external drive so that it can be ejected safely?
I find this interesting since it seems to be a common phenomenon but I haven't found a single clear cut explanation or solution to these issues? What makes it more interesting is that I, at home, have my own personal WD external drive with photos and my CD collection stored on it. This drive is NTFS-3G formatted through MACFUSE and NTFS-3G. This drive has never exhibited the same behavior, the only difference between the discs, except the file system, is that the LaCie contains time machine backups. But since I do not have time machine active, I don't see why this would effect the unmount process.
Another topic I would like some feedback on is corrupted files. When this occurs on a NTFS formated disk used on mac, these cannot be removed. And since Mac and NTFS doesn't play nice, I haven't found a way to resolve this. Disk utility wont work, neither will ntfsfix. The only way around this that I have found is plugging the drive into a windows machine and running chkdsk X: -F
Is there any available alternative for this on Mac that actually works with NTFS disks?
Hoping for some interesting feedback on this from anyone interested
Best Regards
Gus

Answer 1

Hi again Kappy. Thanks for your reply.
1. No, none of the files on the drive are being sent by mail, mail should not have any interest whatsoever in the drive.
2. Most files are created by AMBER 10 and AMBERTOOLS 1.4, molecular dynamics simulation packages. These are UNIX based and I only work with these files from terminal, no GUI. They are created on different servers, downloaded to my MBP and transferred (at least most often) to the LaCie for storage.
3. I have applications stored on the drive through "time machine backups", but I do not run any apps from the drive. Only locally on my MBP, all terminal based UNIX programs are "pathed" correctly to my internal drive.
4. As above, time machine backups my apps, but to my knowledge should not run them from the LaCie drive! Only from my local drive...
5. Disk permissions are full read and write for all. Some files come from /usr/local/ and are specific for my account. But I have taken the habit of "chmod 777" them so I can always access them since I'm the only one with physical access to the LaCie drive.
6. It has at some point, I see no indication of indexing being made in OS X, only through "lsof" where I usually can see spotlight and keychain accessing files. But I have now put the drive under "privacy" from spotlight so it should not index at all now.
7. Yes, once a week a manually perform a time machine backup of my local drive onto the LaCie. Between backups I disable time machine.
8. nine times out of ten I can eject the disc without warning if I first quit mail, iTunes and safari. Same goes if I get the warning, exit the app and then try to eject again. One time out of ten it doesn't seem to matter if I quit all the apps except finder, and ever relaunch finder. Some undetermined apps is still claimed to use the drive. Then the only solution of to force eject.
Best regards
Gus