Error in cmdstanr::read_cmdstan_csv for mixed model, Win 10

Hi there.
I’m trying to run the mixed model below using algorithm = “fullrank” with brms. But I receive the following error after sampling initiates:

Warning: Fitting finished unexpectedly! Use the $output() method for more information.

Error in cmdstanr::read_cmdstan_csv(out$output_files(), variables = “”, :
Assertion on ‘files’ failed: No file provided.

mod1 ← brm(dv ~ 1 + (1|j) + (1|p:j) + (1|d) + (1|i:d) + (1|x) +
(1|j:d) + (1|j:i:d) + (1|j:x) + (1|p:j:i:d) +
(1|p:j:d) + (1|p:j:x) + (1|d:x) + (1|i:d:x) +
(1|j:d:x) + (1|j:i:d:x) + (1|p:j:d:x),, cores = 4, refresh = 5,
algorithm = “fullrank”, backend = “cmdstanr”)

I’m using Windows 10 and have updated rstan and brms.
Any thoughts on a remedy would be appreciated.

Please upgrade cmdstanr to the latest Github development version and try again:


There was a bug in cmdstanr connected to reading CSV with fullrank under some conditions.

Hi Rok! Thanks for the reply.
I successfully updated, but sadly the same error still occurs. Any clues for an alternative approach?