Well, I found the solution here It seems that a new flag must be included in the setup of the jail, so .NET, which uses mlock(2) functions, could properly run. In my case, for a FreeBSD jail, the jail.conf file shall include the following flag: allow.mlock = 1; I noticed that something similar is stated in the instructions for TrueNAS https://emby.media/truenas-server.html But@Luke, please, include this information in the general FreeBSD instructions web, just in a not