# Dealing with Catalina III

**URL:** <https://discourse.mc-stan.org/t/dealing-with-catalina-iii/12731>\
**Category:** RStan\
**Tags:** rstan\
**Created:** [January 21, 2020, 5:33am UTC](https://discourse.mc-stan.org/t/dealing-with-catalina-iii/12731 "2020-01-21T05:33:51Z")\
**Posts on this page:** 1\
**Showing post:** 32

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**Author:** ![andrjohns](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/andrjohns/32/15297_2.png) [@andrjohns](https://discourse.mc-stan.org/u/andrjohns)\
**Post date:** [June 9, 2020, 2:07am UTC](https://discourse.mc-stan.org/t/dealing-with-catalina-iii/12731/32 "2020-06-09T02:07:35Z")

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This is a known issue with RStudio and R4.0 at the moment, you can use the workaround in the below post to get things working again:

> [@R 4.0.0 and CRAN MacOS binaries](https://discourse.mc-stan.org/t/r-4-0-0-and-cran-macos-binaries/13989/19):
>
> I also was having issues with multiple chains running in parallel in MacOS using latest R-4.0.0 and RStan. I’ve found out that this is a problem of the package parallel from R-4.0.0 I’ve found this [recently issue](https://github.com/rstudio/rstudio/issues/6692) in RStudio’s GitHub that solved my problem: cl \<- parallel::makeCluster(2, setup\_strategy = "sequential") If this works, you could add the following to your ~/.Rprofile until this is fixed in R/RStudio: ## WORKAROUND: https://github.com/rstudio/rstudio/issues/6692 ## Revert to 'se…

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