Dear All, I've used PostgreSQL since version 9.x successfully on Linux, macOS and Windows. Today I've upgraded from 12.3 to 13.0 and suddenly I can not start the server any more on Ubuntu 20.04 (inside Docker on Ubuntu 18.04) and on macOS 10.15. I get reproducibly the error: 2020-10-05 11:48:19.720 CEST [84731] WARNING: dup(0) failed after 0 successes: Bad file descriptor 2020-10-05 11:48:19.720 CEST [84731] FATAL: insufficient file descriptors available to start server process 2020-10-05 11:48:19.720 CEST [84731] DETAIL: System allows 0, we need at least 58. 2020-10-05 11:48:19.720 CEST [84731] LOG: database system is shut down What makes this quite curious is that everything continues to work on Ubuntu 18.04, and Windows with Visual Studio 2019. I compile postgreSQL myself from source, but there are no patches or tweaks involved (that I could think relevant for this problem). I've searched for the particular error and understand that it is usually caused by system limits on new files(?) But in my case, the failing setups are relatively modern, powerful CI test machines, with virtually no load at the time of test. On Linux Ubuntu 20.04, `ulimit -n` shows `1048576` which seems also relatively high (but must be the default, not changed by me). Does this problem mean anything to anyone? I'm completely lost where to go from here, or what to try next :-( Help would be greatly appreciated! All the best, Mario Emmenlauer