Datto RMM: macOS Datto RMM Agent Service start fails with error "Object Reference Not Set To An Instance Of An Object"



The Datto RMM Agent service fails to start, and surfaces the error message, "Object reference not set to an instance of an object."


  • Datto RMM
  • Mac OS


When this occurs. the agent icon in the menu bar is red and the About section shows an error similar to the screenshot below:

Figure 1: Datto RMM Agent service error (click to enlarge)

To resolve, Check that the device's hostname ends in .local. If not you must associate the loopback address ( with the hostname in the device's hosts file:

1. Open a terminal session on the device and run the following:

sudo sh -c 'echo " $(uname -n)" >> /etc/hosts'

2. Reboot the device.

If the issue persists, contact Datto RMM Technical Support.

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