Managed computers, the kind most hospitals and universities issue, add security layers that R sometimes trips over. Every problem on this page has been hit by a real tester and has a known fix. Work down the page until yours appears.
Whatever went wrong, the fastest first step is the same:
It checks your R version, your package library, and whether your network can reach the package servers, then names what needs fixing and offers to fix it.
The message is misleading. Your R version is fine.
gradethis is simply not on CRAN, the main package server,
so the ordinary install.packages("gradethis") cannot find
it and R blames your version instead of saying so.
Most often this means the course was installed without its packages,
which happens when the dependencies = TRUE part of the
install command is left off. Let the course install what it needs:
That looks in the right place (Posit’s R-universe server) and, if your network blocks that server, falls back to installing from GitHub automatically. To do it by hand instead, type this into the Console:
A lesson was opened before all the packages it needs were installed,
and usually the missing one is gradethis (see above). Run
check_setup(install = TRUE), say yes to the prompts, then
open the lesson again.
If the error quotes a strange address such as
protect.checkpoint.com or
safelinks.protection.outlook.com, the command was copied
out of an email. Many workplace email systems rewrite every web address
in a message for scanning, including addresses inside code, which breaks
the command. Copy commands from this website or from the Get started guide, or type them in by
hand. Never copy R code out of an email.
Nothing on your computer is broken, and the cause is not anything you
did. This appears when the course is installed from GitHub with
remotes::install_github() rather than with the command in
the Get started guide.
GitHub allows 60 anonymous requests an hour from any one network address, and a hospital or university sends everybody’s traffic out through a single shared address. Colleagues installing the course on the same morning spend that allowance between them, and whoever arrives after it runs out sees the 403. The message names the hour at which it resets, so waiting is a fix in itself.
The better answer is to install from the course’s own server, which has no such limit:
install.packages("r4clinstats",
repos = c("https://apsmunro.r-universe.dev",
CRAN = "https://cloud.r-project.org"),
dependencies = TRUE)Should your network block that server too, download the course as an ordinary file. A plain download does not count against the GitHub limit:
install.packages("remotes")
remotes::install_url(
"https://github.com/apsmunro/r4clinstats/archive/refs/heads/master.tar.gz",
dependencies = FALSE)The dependencies = FALSE is deliberate: it stops R going
back to GitHub for the rest. Follow it with
check_setup(install = TRUE), which fetches the course
packages from CRAN and R-universe.
Some networks only allow traffic through a proxy server, and R does
not always pick that up. check_setup() reports this as
failing to reach CRAN. Two things to try:
http_proxy and https_proxy environment
variables.If CRAN works and only gradethis fails, your network is
likely blocking the R-universe server; the automatic GitHub fallback
described above usually gets around it. Should every route fail,
download the Windows gradethis bundle in your ordinary web
browser from rstudio.r-universe.dev/gradethis
(the .zip under Downloads), then install the file
directly:
On many managed machines your Documents folder lives inside OneDrive,
and R puts its package library there by default. OneDrive can lock files
while it syncs, which corrupts installs. check_setup()
spots this; the fix is one command:
It creates a package library outside OneDrive and points R at it.
Restart R afterwards (Session ▸ Restart R), then
reinstall the course packages with
check_setup(install = TRUE).
> prompt, or looks frozenNothing is broken: a lesson is still running. A lesson holds on to your R console for as long as it is open, and closing the browser tab does not give it back, because the lesson runs in R rather than in the browser.
Click into the Console and press Esc,
or click the red stop button at the top right of the Console pane. The
> prompt returns, and learn() lists the
lessons again.
Your R session is holding an older view of the package, typically
right after installing or updating it. Restart R (Session ▸
Restart R), run library(r4clinstats), and try
again.
A dependency occasionally missed when finalfit installs.
Install it directly:
Open an issue at the project page.
Paste the exact red text you saw, along with the output of
check_setup(), and say whether you are on a work-managed
computer. Those three things are usually enough to diagnose it in one
reply.
> prompt, or looks frozen