Knowledge Base

No data displayed in PRTG Live Graph

The normal Data view of PRTG offers up to four different graphs which can be displayed simultaneously:

  • Live Graph
  • Custom Averages
  • Hourly Averages
  • Daily Averages

If monitoring data is available for the defined timespan each graph should display the respective data. However, in the event that a sensor’s live graph is not displaying any data, while all other graphs are, there are a couple of methods of solving this issue:

  1. If all sensor graphs are being affected

    Under “Extras -> Options” head to the “System” branch and click on the “Recalculate Historic Data” button. The historic data will begin recalculating in the background – the entire process may take some time, so please wait until recalculation has been completed (the recalculation’s status can be discerned at the bottom of the interface).

  2. If recalculating the historic data fails

    Stop PRTG altogether (both GUI and service) and delete the “Cache” subdirectory located under your data directory (default would be C:\Documents and Settings\All Users\PRTG Traffic Grapher\Default). Then, restart PRTG. PRTG will now recalculate the historic data and generate new cache entries. Please bear in mind this process can take a while, depending on the amount of sensors that need to be recalculated.

  3. If individual graphs are being affected

    Edit the sensor in case and under “Sensor Settings -> Advanced” enable the spike filter checkbox. Leave the dialog by clicking the “OK” button. Immediately afterwards edit the sensor anew and disable the spike filter (if you have defined a spike filter for the sensor, follow the reverse procedure). This process will recalculate the historic data for the individual sensor.

If none of these procedures provides a solution please check your PRTG log files for any error messages, such as read / write errors or sensor counter changes which could account for the problem.

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PRTG Traffic Grapher V6