Error Installing mingw32-make and g++ with Rtools44: Installation of the toolchain failed.

[JonRBrauer]

Describe the bug
After updating to R 4.4.1 and Rtools 4.4, new installations of cmdstanr fails at installation of toolchain. Persistently receive following error:

Installing mingw32-make and g++ with Rtools44
Error:
Installation of the toolchain failed. Try reinstalling RTools and trying again.
If the issue persists, open a bug report at https://github.com/stan-dev/cmdstanr.

Steps & checks performed:

Uninstalled all versions of Rtools and reinstalled Rtools 4.4.

Assessed whether R could find Rtools:
devtools::find_rtools()
(TRUE)

Tested ability to install packages from sources using Rtools:
install.packages("Rcpp", type="source")
(it works)

Installed rstan to check Rtools interface & compiling:
example(stan_model, package = "rstan", run.dontrun = TRUE)
(it works)

Examined whether Rtools was discovered on path
Sys.getenv("RTOOLS44_HOME")
Sys.getenv("PATH")
readLines("~/.Renviron")
(Deleted an old .Reviron file pointing to Rtools40 from Documents folder)

To Reproduce

Install cmdstanr, then run:
cmdstanr::check_cmdstan_toolchain(fix = TRUE))

Expected behavior
Successful installation of cmdstanr & toolchain

Operating system
Windows 10 Enterprise

CmdStanR version number
0.8.1
freshly installed in two ways:
install.packages("cmdstanr", repos = c('https://stan-dev.r-universe.dev', getOption("repos")))
remotes::install_github("stan-dev/cmdstanr", force=TRUE)

Additional context

cmdstanr::install_cmdstan()
Error:
Rtools44 installation found but the toolchain was not installed.
Run cmdstanr::check_cmdstan_toolchain(fix = TRUE) to fix the issue.
cmdstanr::check_cmdstan_toolchain(fix = TRUE)
Installing mingw32-make and g++ with Rtools44
Error:
Installation of the toolchain failed. Try reinstalling RTools and trying again.
If the issue persists, open a bug report at https://github.com/stan-dev/cmdstanr.

[jgabry]

Sorry for the slow reply and for the installation issues. Were you ever able to get this working? I'm not a windows user and have limited ability to debug windows installation issues. @rok-cesnovar or @andrjohns, any ideas?