To gain further understanding of the behaviour of grid forming inverters, investigations are carried out in the context of the research project “Fuchstal-leuchtet”. This project includes a field measurement campaign, where the inverters are subject to different tests in an island grid. In addition to the measurements of the campaign, simulations in PSCAD are carried to validate the behaviour of the inverters model, which is being provided by the inverter’s manufacturer. This paper looks at the behaviour of grid forming inverters when experiencing transformer inrush current, since this has proven to be a problem at the start of the measurement campaign resulting in the shutdown of the inverter. The focus of the investigations lies on the behaviour of the inverters control during inrush current and possible measures to prevent shutdowns due to inrush currents in the following field measurement campaigns.