Everyone will have noticed the typical Apple file (.DS_Store) in a folder. This is part of the metadata that allows Spotlight to quickly index the contents of a folder. Unfortunately, Apple also creates these metadata files on USB sticks for each folder and its contents.

If this behaviour is undesirable, it can be deactivated with these two commands in the terminal.

sudo defaults write com.apple.desktopservices DSDontWriteNetworkStores -bool true

sudo defaults write com.apple.desktopservices DSDontWriteUSBStores -bool true