Not All Selected Files Getting Backed Up

I've selected 3 folders to backup: music(150gb), videos(200gb), and misc(100gb). I tried using 7z on ultra, and the job completed successfully, but only the music folder was backed-up/compressed, and the 7z file was 147gb. The contents of the 7z file was verified by exploring it with 7zip, and by examining the Toucan backup log.

I'm not sure what's going on here, I could sure use some help.

I should also note that the backup/compression took something like 20hrs on an i5-2500k, 8gb ram, Win7 on SSD, backing up from a 2tb hdd to a 500gb external drive.

I've saved the job in Toucan, and when I pull it up all three folders (music, movies, misc) are listed under "Files to Backup"

Any help is appreciated