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Free disk space (Multi Drive) sensors on server devices getting results from other server devices



Strange issue...

Every day there will be one device (Windows server) which is getting Free Space results from a totally different server for about 20 minutes.


Server1 Free space will show C drive=12GB free and this is true.


Server1 Free space will suddenly show C drive=39GB and E drive=129GB free and this is not true. Server1 does not even have an E drive.

then the results will go back to normal after 20 minutes, C drive=12GB and E drive=0GB free (because there is no E drive, so PRTG thinks it's gone missing!)

I searched around and found that another server (server2) has C drive=39GB and E drive= 129GB free.

So it looks like PRTG is displaying results for server1 from server2.

This is happening to random servers, different probes. Server1 is on one probe and it's getting results from server2 which is on another probe. So this problem is probe-agnostic.

There have been no IP changes or anything like that, and it's been happening to a random server every day at a random time.

Any ideas?


multi-drive results sensor

Created on Sep 28, 2016 11:46:56 PM

1 Reply



Hi Joe,

Yes, very strange indeed. We observed issues like these, but only with sensors on the same probe system, because something in the DCOM/WMI/RPC realm went haywire.

Here's what you can do:

  • Download our WMI Tester: https://www.paessler.com/tools/wmitester
  • When you observe this issue, start WMI Tester on the responsible probe
  • In tab "Basic" you congfigure the target device and credentials
  • In tab "Advanced" switch to custom and enter the following query below: SELECT DriveType,DeviceID,FreeSpace,Size,VolumeName FROM Win32_LogicalDisk WHERE DriveType=3

The query lists all found drives. Make sure to use the same IP/hostname as in PRTG. We sometimes have cases where in PRTG the IP of a device is configured and when the user connects with RDP to the device, the hostname/fqdn is used (or vice versa) and then suddenly it comes out that the name does not resolve to the expected IP, which then explains unexpected values.

Kind regards,


Created on Sep 30, 2016 1:51:59 PM by  Erhard Mikulik [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.