This article applies as of PRTG 26
Log files
PRTG objects create many log files, with each scanning interval bringing in thousands of points of data. Naturally, these log files take up space on a system. Besides managing how much historic data PRTG retains, we also recommend that you check the PRTG system requirements to make sure your system still meets the recommended system set up.
If your system reports low disk space and you want to delete older logs to clear up space, you need to delete them manually in the PRTG program directory or adjust the historic data purging configuration and wait until PRTG deletes the files automatically.
Historic data purging via PRTG UI
You can manage the details of how PRTG retains historic data via Setup | System Administration | Core Server | Historic Data Purging. All values are the number of days for which PRTG keeps the data before deleting it. If you change these values, PRTG can take up to 24 hours to apply the changes and delete existing historical data.
Note: The Historic Data Purging feature only deletes data on the PRTG Core server; it does not delete data on any remote probe systems.
Manually purge historic data
It is not possible to manually force PRTG to delete log files. To instantly delete log files, navigate to the PRTG data directory: \ProgramData\Paessler\PRTG Network Monitor\Log Database. You can delete all logs or sort by age and delete only older logs.
The ProbeWMI.log file can be deleted manually, however you need to stop the PRTG probe service beforehand. When you start probe service again, the probe creates a new ProbeWMI.log file.
