Install R-cran-ps from repository. > library(ps) > ps_pids() Error in ps_pids() : Not implemented for this platform > p <- ps_handle() Error: Not implemented on this platform: `ps_handle` The "make test" passed because the `test_check` runs only ps_is_supported() - but for me it's false! The last line of tests/testthat.R: if (ps_is_supported()) test_check("ps", reporter = reporter)