What is this?

This knowledgebase contains questions and answers about PRTG Network Monitor and network monitoring in general.

Learn more

PRTG Network Monitor

Intuitive to Use. Easy to manage.
More than 500,000 users rely on Paessler PRTG every day. Find out how you can reduce cost, increase QoS and ease planning, as well.

Free Download

Top Tags

View all Tags

remote probe data loss




a Network with a remote probe had no internet-access for two days. The time the remote probe couldn't reach the prtg server is shown blank in all graphs an the tables. Shouldn't the remote probe store some data an send it to the server when reachable again? On the Server with the remote probe, there are no logs in C:\Documents and Settings\All Users\Application Data\Paessler\PRTG Network Monitor\Logs for exactly that time. Is there a possibility to recover that data?

data loss remote-probe

Created on Mar 21, 2013 4:57:21 PM

1 Reply

Accepted Answer



This might be just a caching issue. Please try the following:

  • Stop both PRTG services (core and probe).
  • Head to your data folder (can be discerned from the PRTG Server Administrator tool, under the Core Server tab)
  • Delete the PRTG Graph Data Cache.dat file
  • Restart the PRTG services
  • Log in to the Web GUI
  • Go to Setup | System Status and check the background tasks. It should state that it is calculating historic data


  • Refresh the page from time to time (is the number being reduced?)
  • Let it run until it is done and then take a look at the historic data of your sensors - it should now be available

Created on Mar 22, 2013 2:18:01 PM by  Torsten Lindner [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.