Something for you guys to try. I noticed my inkeeper updated today after I opened it for the first time in months. That being said, it still wouldn't sync after multiple attempts of closing the apps and opening them again. I ended up running inkeeper as administrator (even though my user is a local admin, I still had to right click and run as administrator). After doing that, it synced on the very next try.
Pro tip, go to the actual .exe file, right click and go to the compatibility tab. At the bottom, check the box for "run as administrator", this will prevent you from having to manually right click and run as admin every time.