If you don’t have a rooted device, you can still copy files to the eternal SD card by hand by using ES File Explorer to do so. For whatever reason, despite the incompability with the 4.3 update, ES File Explorer can still read and write to the SD card.
Grab it here: Download ES File Explorer
If you’ve got your phone rooted and don’t mind playing around a bit, you can also fix the problem yourself. Keep in mind this is done at your own risk.
Head over to /system/etc/permissions/platform.xml and either add in Line 71 (the highlighted one in the screenshot above) from your phone or pull it to your computer and do it there.
<group gid=”media_rw” />
Either way, you’ll need your device to be rooted to have access to this area and all you’re doing is telling your device that it’s allowed to write to the SD card. So yeah, a relatively easy fix when it comes down to it but one that got overlooked when getting Android 4.3 out the door.
If you’re the type of person who doesn’t want to use another program and doesn’t like the idea of rooting your phone, you might just want to wait around for an official update to be rolled out.