It's been days since i expected some replyes from the registration but now it came.
I couldn't wait

So here goes.
As i understand it, the collection updater watches the folder/s for changes using d/inotify or whatever other mean.
Now here's a case in point.
Amarok is humming along nicely playing stuff and you start copying/downloading whatever files somewhere in the dir tree that's watched.
After a while (some seconds) the updater sees some changes and starts scanning.
The thing is, the copying of files is not done so there will be a battle/race condition between the updater and copyer.
As soon as the updater adds a file, it sees another change and starts over ....

Can't it check for change, wait some time, and then if activity is still occuring sleep until done and then update ?
Why you ask ?
Well try to copy 2-3 large files (hundreds of Mb) from one hdd to another or on the same one simultaneously. That would be painfull.
Even more so if your PC is not the master of the universe rather a humble one.

Thanks for this great player !

PS
I'm loaded on 1.4.5 that came with feisty 

There's actually no race during the scan, as we don't check for updates after the scan has started. Only afterward we start checking again.

Maybe i was not clear enough (it happens).
Amarok sees changes. It starts the updater.
The thing is that at the same time some copy/move I/O operation is taking place.
So both the updater and the other process is fighting for disk time.
This can be slow (dead slow ring a bell ?) as both are rather heavy I/O ops.

What i actually wanted is some way for amarok to realise that a "long change"
operation is taking place and hold the updater until it's finnished.

Disk I/O is not cheap (for me at least).

As i've read on another topic, you or somebody from the amarok team suggested that
first copy/download somewhere else then move all at once to the desired folder.
This may seem reasonable but in practice it's not allways so.

I understand this is just a workaround, but why don't you just close Amarok when you need to perform massive disk operations?