Error after installing Nero Express

Hello I have Nero installed in my system and I am sure that it is completely good and no problem with installation and then I encountered an error and don’t know the reason for that error and I got 2 options Yes and No so I am not getting what to select and the error is that your disc is not empty and the image is as follows and kindly provide me solution.
Thank You.

Error:
The disc you have inserted is not empty,but the writing mode of your completion is'Start multisession'or'nomultisession'.
This will cause the information already on the disc to be inaccessible via Windows Explorer.
Should Nero proceed with writing to this disc?
