The Covid-19 pandemic took most EU Member States of the European Union by surprise, as they underestimated the rapid spread of the contagion across the continent. The response of the EU Member States was asymmetrical, individualistic and significantly slow. The first measures taken were to close down the internal borders. The response of the European Union was even slower, and it was not until 17th March 2020 that the external borders were closed. These actions affected legal migration into the European Union from four perspectives: it affected 1) the mobility of those third-country nationals who were on a temporary stay in the EU Member States; 2) the entry of third-country nationals to do seasonal work; 3) legal migrants entering and staying; and 4) the status of the third-country nationals already residing in the EU Member States, especially those experiencing a loss of income. This article will deal with the measures taken by the EU Member States to manage the immigration services, as a case study how Luxembourg dealt to avoid that temporary staying migrants and regular migrants fall into irregularity. Finally, we will focus on the vulnerability of third-country nationals with the rising risk of unemployment and the risk of being returned to their country of origin. The article will also analyse access to healthcare and unemployment benefits.