I'm as familiar with an SD card in Android phone as probably most people are or at least common people. But this issue is driving me crazy and it began today. The files on my SD card are accessible I'm able to delete and move files from one folder to another on the SD card but I cannot move files from internal storage to the SD card at all. I'm getting the message cancelled. I think it may be a setting because I was playing around with the phone today and using third-party apps. Can someone please help me and please don't recommend formatting the card because I really would rather not invest that much time since it's almost two hundred gigs. Thank you.
If you were messing with apps on the phone itself, then likely that is where the problem lies. Have you tried the most simple fix of restarting (turning it off and back on) the phone to see if that resolves it? If not, I would start there.
Should that not work, then I would suggest uninstalling what ever apps you installed, restart again, and see if it works to move files.
Now if it isn't working at this point, and I am assuming you are moving around files on the card through a file manager app, try connecting the phone to a computer via USB cord. Then see if you can move files from the phone to the card via the computer. It should allow it as long as the card it is good. If it still will not allow moving, then you may well need to move all the files on the SD card over to an empty folder on the computer and format the card.