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Historical Data lost after upgrade



I updated to v9.2.1.2308 and lost all historical data over 2 days. How do I see the data going back longer?

historical prtg upgrade

Created on Apr 26, 2012 3:33:59 PM

3 Replies

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 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 ->PRTG Status-> 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 Apr 26, 2012 4:56:36 PM by  Torsten Lindner [Paessler Support]



This worked smashingly well. Thanks for the assistance.

Created on Apr 26, 2012 6:10:23 PM



Bout time to revive an old thread. I just upgraded to and lost my history. How do I get it back?


Created on Nov 6, 2019 6:24:23 PM

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.