You can capture traces on the device, through Winscope, or through Android Debug Bridge (adb) commands.
In Winscope, you can retrieve the latest traces collected from a device during the previous session. This feature is especially helpful when facing connection issues, such as using ADB over Wi-Fi, or when Winscope closes unexpectedly. If there are no traces from the last session, Winscope displays No valid trace files found.
Error messages
Winscope shows the following messages during trace collection:
| Message | Description |
|---|---|
| No trace targets selected | No trace checkboxes are selected. |
| Errors occurred during tracing: ERROR: INVALID_LAYER_STACK, please
check your display state (must be on
at start of trace) |
A screen recording was requested, but the display was off at the start of trace. |
| Errors occurred during tracing: A specific error message received from adb command, such as Failed to find valid files for <trace types requested> |
adb couldn't read the trace files, which typically happens when adb isn't running as root. |
| Errors occurred during tracing: Tracing time out | There's a connection issue with the device. |
| Errors occurred during tracing: {inner error} | This message covers all other errors. |