diff --git a/R/nix_build_helpers.R b/R/nix_build_helpers.R
index b2c2a43e..fe4363c5 100644
--- a/R/nix_build_helpers.R
+++ b/R/nix_build_helpers.R
@@ -115,6 +115,14 @@ poll_sys_proc_nonblocking <- function(cmd,
 
   status <- sys::exec_status(proc, wait = TRUE)
 
+  if (is.na(status)) {
+    tools::pskill(pid = proc)
+    stop(
+      "`nix_build()` likely interrupted by SIGINT (ctrl+c)\n",
+      "Stop process with PID ", proc
+    )
+  }
+
   if (isFALSE(is_quiet)) {
     if (status == 0L) {
       cat(paste0("\n==> `", what, "` succeeded!"))
diff --git a/R/with_nix.R b/R/with_nix.R
index 5b1e7b43..7c144106 100644
--- a/R/with_nix.R
+++ b/R/with_nix.R
@@ -326,10 +326,12 @@ with_nix <- function(expr,
     if (nzchar(LD_LIBRARY_PATH_default)) {
       # set old LD_LIBRARY_PATH (only if system's R session and if it wasn't
       # `""`)
-      on.exit({
-        Sys.setenv(LD_LIBRARY_PATH = LD_LIBRARY_PATH_default)
-      },
-      add = TRUE)
+      on.exit(
+        {
+          Sys.setenv(LD_LIBRARY_PATH = LD_LIBRARY_PATH_default)
+        },
+        add = TRUE
+      )
     }
   }
 
diff --git a/tests/testthat/test-fetchers.R b/tests/testthat/test-fetchers.R
index 39236fd4..c2aa8b01 100644
--- a/tests/testthat/test-fetchers.R
+++ b/tests/testthat/test-fetchers.R
@@ -1,4 +1,5 @@
 testthat::test_that("Test fetchgit works", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchgit(
       list(
@@ -12,6 +13,7 @@ testthat::test_that("Test fetchgit works", {
 })
 
 testthat::test_that("Test fetchgit fails gracefully", {
+  testthat::skip_on_cran()
   testthat::expect_error(
     fetchgit(
       list(
@@ -24,6 +26,7 @@ testthat::test_that("Test fetchgit fails gracefully", {
 })
 
 testthat::test_that("Test fetchgit works with gitlab packages", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchgit(
       list(
@@ -39,6 +42,7 @@ testthat::test_that("Test fetchgit works with gitlab packages", {
 
 
 testthat::test_that("Test fetchzip works", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchzip("AER@1.2-8"),
     "\n    (pkgs.rPackages.buildRPackage {\n      name = \"AER\";\n      src = pkgs.fetchzip {\n       url = \"https://cran.r-project.org/src/contrib/Archive/AER/AER_1.2-8.tar.gz\";\n       sha256 = \"sha256-OqxXcnUX/2C6wfD5fuNayc8OU+mstI3tt4eBVGQZ2S0=\";\n      };\n      propagatedBuildInputs = builtins.attrValues {\n        inherit (pkgs.rPackages) \n          car\n          lmtest\n          sandwich\n          survival\n          zoo\n          Formula;\n      };\n    })\n"
@@ -46,6 +50,7 @@ testthat::test_that("Test fetchzip works", {
 })
 
 testthat::test_that("Test fetchzip fails gracefully", {
+  testthat::skip_on_cran()
   testthat::expect_error(
     fetchzip("AER@999999"),
     "Are these correct?"
@@ -53,6 +58,7 @@ testthat::test_that("Test fetchzip fails gracefully", {
 })
 
 testthat::test_that("Test fetchgits", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchgits(
       list(
@@ -73,6 +79,7 @@ testthat::test_that("Test fetchgits", {
 })
 
 testthat::test_that("Test fetchzips works", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchzips(
       c("dplyr@0.8.0", "AER@1.2-8")
@@ -83,6 +90,7 @@ testthat::test_that("Test fetchzips works", {
 
 
 testthat::test_that("Test fetchpkgs works", {
+  testthat::skip_on_cran()
   testthat::expect_equal(
     fetchpkgs(
       git_pkgs = list(
diff --git a/tests/testthat/test-rix.R b/tests/testthat/test-rix.R
index 88bda9e2..25290826 100644
--- a/tests/testthat/test-rix.R
+++ b/tests/testthat/test-rix.R
@@ -400,13 +400,14 @@ testthat::test_that("rix(), frozen_edge", {
   )
 
 
-  on.exit({
-    system(
-      paste0("sed -i 's/", frozen_edge_commit, "/REVISION/' _snaps/rix/frozen_edge_default.nix")
-    )
-    unlink(path_default_nix, recursive = TRUE, force = FALSE)
-  },
-  add = TRUE
+  on.exit(
+    {
+      system(
+        paste0("sed -i 's/", frozen_edge_commit, "/REVISION/' _snaps/rix/frozen_edge_default.nix")
+      )
+      unlink(path_default_nix, recursive = TRUE, force = FALSE)
+    },
+    add = TRUE
   )
 })