Brms Error in file.exists( rstan_options("boost_lib"))

Hello, after updating my OS and R / RStudio, brms ran fine for a while but now I get the following error:

Error in file.exists(rstan_options(“boost_lib”)) :
invalid ‘file’ argument
In addition: Warning message:
In (function (x) : rstan option ‘boost_lib’ not found"

I get the error when I try to run my real model, but also when trying to run

example(stan_model, package = "rstan", run.dontrun = TRUE)

from the installation guide. I am really confused because after the update everything was fine. The full output of the example is as follows

Loading required package: StanHeaders
rstan (Version 2.21.8, GitRev: 2e1f913d3ca3)
For execution on a local, multicore CPU with excess RAM we recommend calling
options(mc.cores = parallel::detectCores()).
To avoid recompilation of unchanged Stan programs, we recommend calling
rstan_options(auto_write = TRUE)

Attaching package: ‘rstan’

The following object is masked from ‘package:tidyr’:


stn_md> stancode ← ‘data {real y_mean;} parameters {real y;} model {y ~ normal(y_mean,1);}’

stn_md> mod ← stan_model(model_code = stancode, verbose = TRUE)

TRANSLATING MODEL ‘16a540c6086086816528e4524def24d9’ FROM Stan CODE TO C++ CODE NOW.
successful in parsing the Stan model ‘16a540c6086086816528e4524def24d9’.
COMPILING THE C++ CODE FOR MODEL ‘16a540c6086086816528e4524def24d9’ NOW.
OS: x86_64, darwin20; rstan: 2.21.8; Rcpp: 1.0.11; inline: 0.3.19

I have not found any entry for this error and will appreciate your help greatly. Thank you already in advance!

I am not sure, but I would definitely try reinstalling rstan and also BH. What is the contents of rstan_options(“boost_lib”) on your computer? This could also provide some hints…