kiwi.ds isn't repacking .narc file properly

[Natural21]

Hello! I'm making a fun custom ROMhack for myself and I'm almost done. I've edited a whole bunch of things and I'm just finishing up by adding a new sprite. However, I've come across a problem where whenever I use kiwi.ds to try and repack the .narc folder that the sprites are in, it repacks it as a file over ten times as large as it should be.

Here are some screenshots of what I'm dealing with:

As you can see, the initial extracted .narc (Initial) and its unpacked folder are only around 7mb. However, the repacked file (Completed) is stupidly large. I've already tried reinserting the new .narc into the ROM and what happens is that the "Pokemon Company" screen shows up and then a black screen appears with no sound.

If anyone has any idea why this is happening, I would be so grateful for some advice. I'm almost done this mod and this is the last roadblock I have to overcome. Please let me know if there are any more details or screenshots I need to provide!

[Natural21]

Update: I figured out a solution! I was doing all the unpacking, repacking, and extracting on an external hard drive, which had been working fine until this point. I tried moving everything onto my computer's main drive and repacking it all there and it worked perfectly! Probably just had something to do with the storage size of the extract folder on the hard drive.