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PRTG keeps restarting probe service when installed on an Amazon EC2 instance. What can I do?



I have installed PRTG in the Amazon cloud. Looking into the log files, I can see that PRTG constantly restarts the probe service because of a No Message Timeout error.

The log file shows the following:

10/19/2010 9:16:52 PM Connected to prtg.example.com:23582
10/19/2010 9:16:53 PM Need Login
10/19/2010 9:16:53 PM Connected
10/19/2010 9:16:58 PM Send Login
10/19/2010 9:16:58 PM Login OK: Welcome to PRTG
10/19/2010 9:17:11 PM Server TimeSync from 10/19/2010 9:19:47 PM to 10/19/2010 9:17:13 PM
10/19/2010 9:17:30 PM No Message Timeout, last message was 10/19/2010 9:17:13 PM
10/19/2010 9:17:37 PM Trying to restart PRTG Probe. Reason: Connection Watchdog: Last ping 10/19/2010 9:21:45 PM
10/19/2010 9:17:38 PM Restart initiated

amazon cloud ec2 probe prtg restart timesync

Created on Nov 4, 2010 3:19:51 PM by  Daniel Zobel [Product Manager]

Last change on Nov 4, 2010 4:18:50 PM by  Daniel Zobel [Product Manager]

3 Replies

Accepted Answer



This article applies to PRTG Network Monitor or later running on Windows Vista or later.

Change Time Query Method

In combination with a virtual machine, for example an Amazon EC2, there may be an incompatibility in the way time is queried via QueryPerformanceCounter. In order to switch PRTG to another method to query time, you can add a registry value.

Caution: Please backup your system before manipulating the Windows registry!

Step 1

Step 2

Open the registry editor.

  • For a 64-Bit Windows system, go to HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Paessler\
  • For a 32-Bit Windows system, go to HKEY_LOCAL_MACHINE\SOFTWARE\Paessler\

Step 3

  • Add a new DWORD value with the name timer.
  • Set its value to 1.

Step 4

  • Restart core server and probe services.


  • This alternative query method may be less accurate and result in incorrect time measurements (in a range of milliseconds). This is okay if you only want to monitor availability, but if you need to get exact Ping times, for example, this is not a solution.
  • Only use this setting on Windows versions Vista or later! On systems running Windows XP or earlier, PRTG will not start when this setting is used!
  • A probe restart can also have other reasons; the procedure described here only refers to the possibility that it is caused by a wrong PerformanceCounter on a virtual machine.
  • You might also need to switch off the Windows Administrator account's User Account Control (UAC).
  • The setting is only valid for the core server on which you've just changed the registry. When running a cluster with additional core server installations, please perform these steps on every node to make sure the changed time query method is also set for the other nodes.


For more information, please see AmazonWebServices at http://developer.amazonwebservices.com/connect/thread.jspa?threadID=41426&start=15&tstart=0

Created on Nov 4, 2010 3:35:00 PM by  Daniel Zobel [Product Manager]

Last change on Mar 3, 2011 12:23:53 PM by  Daniel Zobel [Product Manager]



Do the registry changes need to be made only one the computers that are experiencing the problems? Or all just on the server PRTG server? or both?

Created on Nov 9, 2010 6:39:26 PM



Dear Laurie,

on the problematic probe machines.

Best Regards.

Created on Nov 12, 2010 4:48:02 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.