File locations, default location and content

Hoping someone can help me out. I have a new computer that is only 4 months old. I have been saving everything I do to C drive (120GB) like I have always done, now it is full and I cant work on it anymore. I have a D drive that is 2TB so I copied all my documents, photos etc to that drive to free up space on C drive. Now when I try and open up any file on D drive I get the following message     

"Please reconnect the device that has the file location, or choose a new folder. In the meantime, content will be saved in the corel default location. You can move the content after the file location is restored'  Can anyone tell me what that means and what I need to do. Thank you