a chicken-and-egg situation

a chicken and egg situation/problem

A situation in which it is unknown what happened, or what needs to happen, first. You need experience to get a job, but you need a job to get experience. It's a chicken and egg situation.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

a ˌchicken-and-ˈegg situation

a situation in which you do not know which of two connected events is the cause of the other: Is she unhappy because she gets into debt, or does she get into debt because she’s unhappy? I suppose it’s a chicken-and-egg situation.This comes from the question ‘Which came first — the chicken or the egg?’.
See also: situation
Farlex Partner Idioms Dictionary © Farlex 2017
See also:
References in periodicals archive ?
Ironically, this is a chicken-and-egg situation. Which comes first: the infrastructure or the enabling technology?
"It's a chicken-and-egg situation," Philander says.