I just noticed that a process called nsurlsessiond is downloading data from the internet at the maximum rate possible with my internet connection. I tried killing the process but then it came back after few hours. If I kill the process and restart the computer then it comes back again. My data quota is almost about to be over and data is expensive where I live . I have iCloud photo library and iCloud Drive enabled. However, I have not made any changes to any of those online storages (such as adding a new file or deleting a file from it). Please help me to find the root cause of this problem.