This has been irritating me ever since I got my MacBook. I use lots of different computers with lots of different operating systems and the simplest way to transfer information is often to use a FAT32-formatted removable USB flash drive.
On my Windows and Linux machines this works great. I plug in the drive and the files are available. No problem. On my Mac I plug in the drive and it messes with it. It splats a bunch of “hidden” folders on the drive then locks the drive from being dismounted while it spends a lot of CPU cycles attempting to index it. All of which is completely pointless. And there’s no config or preference to switch it off.
Worst of all, it even does it to the memory cards from my camera. This is inexcusable.
Searching around I found a lot of people complaining about this, but no real solutions, until I stumbled on macosxhints.com – 10.4: Disable Spotlight on a FAT32 external drive.
Simply create an empty file at the top level of the drive named .metadata_never_index and the Mac OS X “Spotlight” indexer should leave it alone forever.