Can't backup a subfolder

I have a folder designated for photos and its sub folders are years and consequently many sub for different events. One folder, 2015, was backed up previously, but after adding one more event folder below 2015 in an source drive, the external WD Elements does not allow me the put check mark on event folders so the new files are not backed up. Thanks for your help


What backup software are you using to backup your files?

Thanks for your response. I’m using WD SmartWare Pro Ver. 2.4.12


Have you tried uninstalling and reinstalling WD Smartware?

Thanks Hamlet,
I bought this Pro version online by clicking the Upgrade button in the package included with the drive. This upgrade allows to install on two PCs. Afraid that if I reinstall, I will lose the allowance for my PC. Is that true?