How do I turn off the initial Auto-Discovery?
As of PRTG version 21.2.67, the initial Auto-Discovery can be disabled by using the "Custom" Installation Mode during the installation process. For older PRTG versions, there are the following possibilities:
1) You can disable initial auto-discovery for a fresh PRTG installation, by running the installer in command prompt and adding /NoInitialAutoDisco=1 as parameter. This may be useful for performance reasons or if you prefer to manually add devices and sensors to your installation.
2) If auto-discovery is currently running, you can stop it: right-click the group or device, and select Pause | For 5 minutes... from the context menu. PRTG will pause monitoring for 5 minutes and stop auto-discovery tasks.
3) If initial auto-discovery is already performed, you can delete devices that you don't need.
For more information about auto-discovery, have a look here: https://www.paessler.com/manuals/prtg/auto_discovery