What the LED bar shows
Each displayed drive has two activity indicators and a label.
| Indicator | Meaning |
|---|---|
| Green | Windows reports data being read from the drive. |
| Red | Windows reports data being written to the drive. |
| Both active | Reads and writes are reported during the sampling period. |
| Dim indicators | Little or no recent activity is reported. |
The brightness changes with the activity and fades after a burst, which makes brief accesses easier to see. Sampling is repeated at short intervals, so the bar is an activity indicator rather than an exact record of every individual operation.
Hover over a drive to see its identifying information. The bar shows logical drives, which can be partitions on the same physical device.
What the lights do not tell you
Red means writing; it is not an error light. DriveLED does not identify the process responsible for an access, does not diagnose SMART health and does not estimate the remaining life of an SSD. A dim LED does not prove that a drive is disconnected: the drive can be idle, or Windows does not expose its activity counters.
For an analysis of write accesses by process and file, see O&O VisualDisk, which is supplied with O&O Defrag.