The Trend function requires at least 5 percent free space of the overall hard drive capacity. The Trend function performs a validation test while it is running to verify that there is at least 5 percent of the overall drive capacity available.
If the Trend curve appears to be reacting sluggishly or seems to be locked up, it's possible that free available space could be nearing or below the minimum 5 percent free space. If the free available space is well below the 5 percent required minimum, the Trend function could stop working.
To resolve the issue, ensure that there is at least more than 5 percent free space of the total capacity on the hard drive.