[ddouglass]

If you imported them as KMA with 4.11 or older then yes. Which means you have two complete files For example, if a ZIP file is 5.4MB then you have a KMA file that is 5.4MB also, for a total drive space (split between both drives yes) of 10.8MB and it took you any where from 15 to 30 seconds to import that file.
Now if you import the same file using 4.20 you have a ZIP file of 5.4MB and a KMH file of 4KB (smallest size sector most drives are set too) and you don't need another copy on the external drive. Also the import time is roughly .1 of a second for each file.
This also applies for MP3+G, Video, MP3,and WMA files. The reason for doing this is all of these types are already compressed, so Hoster does not add any more compression to them. Also it allows you to be able to use any of these types in other programs without needing to have the original and a KMA file or in other words half to space taken up on your drives for multiple program use.
Read the whole section on Importing from Hard Drive in the manual. It gives very detailed explanation of this.