~350 back up on a 1TB HDD... Can I choose what to specifically put on new..

Question

Long story short, I spilled water on my macbook and am contemplating getting a macbook air with insurance money to replace it. I had a 500gb hdd in the macbook and it was filled with about 350gb of data and backed up on my external hard drive. The air I get will most likely have 256gb of storage so I plan on putting all my movies and music on the external and keeping apps, etc on the built-in storage.
Obviously I won't be able to restore it all to the new mac, so how can I basically just take the music and movies from the back up and start over with everything else? I may be able to just figure it when I get to that point but I was hoping for some suggestions of some kind. Thanks!

Answer 1

You don't say how large your backup drive is or if it is a bootable back up (like a clone), a Time Machine backup, or just Finder copies of user files or something. This makes giving specific advice a bit hard, but here are some things to consider:
Your 500 GB HD from your drowned MB may still be OK. If so, you could use it in an external drive enclosure or with an inexpensive adaptor (like this one). This would allow you to delete the movies and music files on it (making sure they are safely backed up on the existing backup drive!) & then use it as the source drive with Setup Assistant when you first startup your new MacBook Air. This has the advantage of transferring all your applicable system & user settings, third party applications, & other user files from the MB, saving you the time & effort of setting everything up from scratch.
Alternately, you may be able to do much the same thing with existing backup drive, assuming it is a bootable drive or full Time Machine backup (one that includes system files & the normal boot drive folder layout) & all or most of your movies and music files are in the default "Music" & "Movies" folders of your user's home folder on this drive. This will work because Setup Assistant allows you to migrate users but to exclude certain of its folders, including the "Music" & "Movies" ones. To do this, attach the backup drive before first startup of the MBA & in Setup Assistant choose the "From a Time Machine backup or other disk" option. Choose the backup disk in the "Select your disk" step. In the "Select Items to migrate" step, click the disclosure triangle next to the "Users" box to show the users & check the user(s) you want to migrate. (Note: the disclosure triangles may not appear until the "calculating…" step completes, so be patient.) Click the disclosure triangle next to the user name to show its folders & uncheck the Music" & "Movies" or other folders as needed to reduce the total size of the selected items so they all will fit on the MBA's drive with room to spare for normal use. (The bottom of the window will show you the available space on the drive & the total of the selected items, making it easy to do without guesswork.)
If your existing backup drive is neither a bootable one nor a full Time Machine backup, it will not appear in the Setup Assistant or Migration Assistant "Select your disk" step & you cannot use either assistant to transfer user files, applications, or settings from it to the MBA. For this case, you will need to set up the MBA from scratch & manually transfer selected user files from the backup to the MBA. In general, it is best to reinstall third party apps from scratch & to be careful about what you copy to your user folder. For help with that, see the user tips section at the top of the main Installation and Setup page.