Time Machine failing (.inProgress) My Time Machine recently stopped working. When it tries to create a backup, it quickly fails with the error: 


  "Unable to complete backup. An error occurred while creating the
  backup folder."


The drive has plenty of space and I have not updating my operating system. Actually, due to software compatibility issues, I'm still running 10.9.5. Everything I've found on google says to remove the .inProgress file, but when I try to delete it (drag it to Trash) I get this error: 


  "The Finder can't complete the operation because some data in
  "file.inProgress" can't be read or written. (Error code -36)"


I've tried tmutil delete and it returned the error "tmutil: delete requires root privileges." I don't even know what that means. Can someone give me another suggestion? Manually backing up my hardrive is a huge pain and I forget to do it more often than not.
The user account named ”root” is a superuser with read and write privileges to more areas of the system.

It is disabled by default since it can do a lots of irreparable damages, so use it with caution.

In Terminal use the Sudo to invoke that root user account, and you will be prompted to enter the password, which is usually your Administrator password. It is just a protection for some powerful commands making sure you want to do that by confirming it with password.

sudo tmutil delete …


Password: .....