I've been using an external G-drive with Time machine for years with no issues. Recently, I got an error message saying that there was not enough space on the disk to complete the backup. I went through my files and removed all but the essential ones from the backup, bringing the size well within the space available on the disk. Now Time Machine starts a back up on schedule, but just stops with no error message. There's not a specific point at which it stops (it could be 250mb or 20Gb from 125GB total). I have rebooted the machine (hard reboot and restart multiple times) and set up Time Machine preferences again, neither helps. I also ran Disk Utility and there are no issues with the disk. I am running a MacBook Pro Retina with OS Yosemite Version 10.10.5. Any help would be great! Thanks.