Hi forum,

I have already opened a similar thread here: Brms model doesn't run after custom family (hurdle_gamma()) specified, but haven’t received any replies yet and I am getting quite desperate.

I have been working with different brm models for a while now and never had any problems. Then all of a sudden (I believe this happened after I specified “family = hurdle_gamma()”), the code stopped running entirely and I got a number of different error messages (see above link for a selection).

Now I’ve tried to run an old model which has always run just fine:

```
HALO_bayes$m1 <-brm(formula = HALOAccuracies ~ HALOlg10JerksZ*HALOOwnStimDiff_jerkZ*HALOIntervention*HALOConditions +
(1 + HALOlg10JerksZ*HALOOwnStimDiff_jerkZ*HALOConditions*HALOIntervention || HALOVidIDs) +
(1 + HALOlg10JerksZ*HALOOwnStimDiff_jerkZ*HALOConditions*HALOIntervention || HALOSubs),
data = HALOdat,
warmup = 1000, iter = 5000,
options(mc.cores = parallel::detectCores()),
chains = 4, control = list(adapt_delta = .99),
prior = prior1, sample_prior = TRUE,
save_all_pars = TRUE)
```

I didn’t change a thing in the code. Again, I now receive a bunch of random errors, the first one being:

`Error: Argument 'family' is invalid.`

Then, when I specify “family = gaussian()”, which should not be necessary as it is the default in brm, I receive the following error:

```
Error in formula.default(object, env = baseenv()) : invalid formula
In addition: Warning message:
Argument 'autocor' should be specified within the 'formula' argument. See ?brmsformula for help.
```

I then check ?brmsformula and from what I can understand, ‘autocor’ does not need to be specified. I also can’t see anything wrong about my formula (especially since the model ran fine just a few days ago with this very same formula).

Any suggestions as to what is happening here would be massively appreciated. I am completely lost and at my limits with googling error messages and trying to find the root of the problem.