Hi my name is ***** ***** Dr.Fix-It , Your online expert ready to assist you...
Well since last tried to load books Sony and Kobo readers have merged (CLICK HERE to find out more).
To correct the sync issue please factory reset the Kobo Aura (CLICK HERE for Kobo reset procedure) and install the latest Kobo Desktop software on your computer to get all up to current versions (CLICK HERE to download).
reference syncing information by CLICK HERE.
Please give it a try and let me know if have any questions along the way with a reply....only rate my answer ok, great, or EXCELLENT after we have worked on the issue together to your satisfaction. Bonuses are welcomed & appreciated. I look forward to any future inquires as well, Thank You