I tried everything in this thread and my disk usage was still 100%.
One Drive For Business was definitely the cause, because when I killed the process, disk usage dropped immediately back to normal.
As a last resort, I removed the One Drive for Business Cache. After much cursing at MSFT, there was much relief - it worked.
https://support.microsoft.com/en-us/kb/3038627
Notes:
- Stop sync, then backup the local copies
- For some bizarre reason, the Team documents in Office 365 sync to /User/Sharepoint on my local drive and my personal files sync to /User/One Drive For Business.
- WARNING - THIS WILL RE-SYNC ALL YOUR FILES. YOU MAY LOSE DATA! BACKUP BEFORE RUNNING.