I use Titanium Backup and on the newer Android when using external card for storing backups I was hit by this issue, manifested by backup session being interrupted with a message “Insufficient storage”.
I’m currently on Android 5.1.1 (CyanogenMod 12.1 NIGHTLY) and the following steps helped:
- Edit /system/etc/permissions/platform.xml
- Find the following section
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" > <group gid="sdcard_r" /> <group gid="sdcard_rw" /> </permission>
- Add <group gid=”media_rw” /> to make it look like that
<permission name="android.permission.WRITE_EXTERNAL_STORAGE" > <group gid="sdcard_r" /> <group gid="sdcard_rw" /> <group gid="media_rw" /> </permission>
- Reboot your phone