fa.parallel from R package psych hangs indefinitely

Question

Tried to run parallel analysis via psych -package with the example from the documentation:

library(psych)
fa.parallel(Thurstone, n.obs = 213)

This hangs indefinitely, does not give a warning or an error. R 4.0.1, all packages up to date.

(Note, that I answered this question myself, but am wondering if there is a better solution and what the cause of the problem is.)

Answer 1

There seems to be a problem with multiple cores.

Running only one iteration works:

fa.parallel(Thurstone, n.obs = 213, n.iter = 1)

When using only one core, it also works:

options(mc.cores = 1)
fa.parallel(Thurstone, n.obs = 213)

Not sure why it hangs in the first place, though.