Cut and paste my files to a drive then location is unavailable.

Hey guys,

I backed up my files by cutting and pasting them from my laptop to my drive. But for some reason it has caused two problems which I will tell you guys below.

What I did was I went to C:\Users\Michael, Michael is the folder of my name. Under the folder of Michael, I saw the files that I wanted to back up. I cut and pasted all the files under this folder to my drive. The estimated finish time was 3 hours. Before the process was complete, I stopped once for some reason. Then I came back and restarted the back-up process by doing the same thing - cut and pasted them to my drive.

When it was done, I feel like I've moved all the files I need to my drive, but it has caused a problem - when I open folders like Document, Pictures, Michael, Music and other folders that are under the folder of "Michael" which is where I cut and pasted files from, a window pops up, saying
"Location is not available - E:\2016\backup\ refers to a location that is unavailable. It could be on a hard drive on this computer, or on a network. Check to make sure that the disk is properly inserted or that you are connected to the Internet or your network, and then try again. If it still cannot be located, the information might have been moved to a different location".
"E:\2016\backup\" is the destination folder in my drive where I want my files go to. It seems by cutting and pasting all the files from the folder of Michael, it linked the folder of Michael to my drive.

Also, when I don't have my portable drive connected, there is nothing in "Document" folder. But once I connect my drive, the files that I cut and pasted are shown in the folder. I checked their locations, and they link to my portable drive. I am not sure what happened here. Did I just run into a conflict? Does it mean that some files are missing when I cut and pasted them from the local machine to the drive? What should I do now to fix the "Location Unavailable" problem?

Thank you guys very much!