# Dealing with Catalina

**URL:** <https://discourse.mc-stan.org/t/dealing-with-catalina/11285>\
**Category:** Developers\
**Tags:** rstan\
**Created:** [October 7, 2019, 8:16pm UTC](https://discourse.mc-stan.org/t/dealing-with-catalina/11285 "2019-10-07T20:16:31Z")\
**Posts on this page:** 1\
**Showing post:** 239

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**Author:** ![bgoodri](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mc-stan.org/bgoodri/32/4451_2.png) [@bgoodri](https://discourse.mc-stan.org/u/bgoodri)\
**Post date:** [March 10, 2020, 2:31pm UTC](https://discourse.mc-stan.org/t/dealing-with-catalina/11285/239 "2020-03-10T14:31:41Z")

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Probably doing

```no-highlight
xcode-select --install

```

in the Terminal app or Terminal window of RStudio will do the trick in this case. However, see also

> [@Dealing with Catalina IV](https://discourse.mc-stan.org/t/dealing-with-catalina-iv/13502):
>
> If you are trying to install the pkg from in order to get the C++ toolchain setup on Catalina, then to open it you apparently have to hold down Ctrl while clicking on the installer file that you downloaded. At that point it should look like [[image] ](https://user-images.githubusercontent.com/833642/68826173-5f151400-0662-11ea-8a57-418f88f41ea3.png) and clicking Open will get it going. You probably need to have R 3.6 or later for things to work smoothly. Also, you will probably have to install rstan and related packages from source, via instal…

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