diff --git a/pkgs/build-support/docker/nix-prefetch-docker b/pkgs/build-support/docker/nix-prefetch-docker
index f551d37cda96..7104e155e0ec 100755
--- a/pkgs/build-support/docker/nix-prefetch-docker
+++ b/pkgs/build-support/docker/nix-prefetch-docker
@@ -121,7 +121,9 @@ fi
 
 sourceUrl="docker://$imageName@$imageDigest"
 
-tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/skopeo-copy-tmp-XXXXXXXX")"
+# nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+# to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/skopeo-copy-tmp-XXXXXXXX")")"
 trap "rm -rf \"$tmpPath\"" EXIT
 
 tmpFile="$tmpPath/$(get_name $finalImageName $finalImageTag)"
diff --git a/pkgs/build-support/fetchbzr/nix-prefetch-bzr b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
index 184f2485ce57..2b7a4ccfb39a 100755
--- a/pkgs/build-support/fetchbzr/nix-prefetch-bzr
+++ b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
@@ -42,7 +42,9 @@ fi
 # If we don't know the hash or a path with that hash doesn't exist,
 # download the file and add it to the store.
 if test -z "$finalPath"; then
-    tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/bzr-checkout-tmp-XXXXXXXX")"
+    # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+    # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/bzr-checkout-tmp-XXXXXXXX")")"
     trap "rm -rf \"$tmpPath\"" EXIT
 
     tmpFile="$tmpPath/$dstFile"
diff --git a/pkgs/build-support/fetchcvs/nix-prefetch-cvs b/pkgs/build-support/fetchcvs/nix-prefetch-cvs
index 4438f44026f2..1b47daa77db3 100755
--- a/pkgs/build-support/fetchcvs/nix-prefetch-cvs
+++ b/pkgs/build-support/fetchcvs/nix-prefetch-cvs
@@ -20,7 +20,9 @@ fi
 
 
 mkTempDir() {
-    tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/nix-prefetch-cvs-XXXXXXXX")"
+    # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+    # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/nix-prefetch-cvs-XXXXXXXX")")"
     trap removeTempDir EXIT
 }
 
diff --git a/pkgs/build-support/fetchgit/nix-prefetch-git b/pkgs/build-support/fetchgit/nix-prefetch-git
index 1e8ac0ec66ef..bcb7b434d948 100755
--- a/pkgs/build-support/fetchgit/nix-prefetch-git
+++ b/pkgs/build-support/fetchgit/nix-prefetch-git
@@ -454,7 +454,9 @@ else
     # download the file and add it to the store.
     if test -z "$finalPath"; then
 
-        tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/git-checkout-tmp-XXXXXXXX")"
+        # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+        # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+        tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/git-checkout-tmp-XXXXXXXX")")"
         exit_handlers+=(remove_tmpPath)
 
         tmpFile="$tmpPath/$(url_to_name "$url" "$rev")"
diff --git a/pkgs/build-support/fetchhg/nix-prefetch-hg b/pkgs/build-support/fetchhg/nix-prefetch-hg
index 94c6b1ec6945..bd40a609f5dd 100755
--- a/pkgs/build-support/fetchhg/nix-prefetch-hg
+++ b/pkgs/build-support/fetchhg/nix-prefetch-hg
@@ -43,7 +43,9 @@ fi
 # download the file and add it to the store.
 if [[ -z "$finalPath" ]]; then
 
-    tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/hg-checkout-tmp-XXXXXXXX")"
+    # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+    # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/hg-checkout-tmp-XXXXXXXX")")"
     cleanup() { x=$?; rm -rf "$tmpPath"; exit $x; }; trap cleanup EXIT
 
     tmpArchive="$tmpPath/hg-archive"
diff --git a/pkgs/build-support/fetchsvn/nix-prefetch-svn b/pkgs/build-support/fetchsvn/nix-prefetch-svn
index 03b9eb9a03df..8adbe803f2ec 100755
--- a/pkgs/build-support/fetchsvn/nix-prefetch-svn
+++ b/pkgs/build-support/fetchsvn/nix-prefetch-svn
@@ -41,7 +41,9 @@ fi
 # If we don't know the hash or a path with that hash doesn't exist,
 # download the file and add it to the store.
 if test -z "$finalPath"; then
-    tmpPath="$(mktemp -d "${TMPDIR:-/tmp}/svn-checkout-tmp-XXXXXXXX")"
+    # nix>=2.20 rejects adding symlinked paths to the store, so use realpath
+    # to resolve to a physical path. https://github.com/NixOS/nix/issues/11941
+    tmpPath="$(realpath "$(mktemp -d "${TMPDIR:-/tmp}/svn-checkout-tmp-XXXXXXXX")")"
     trap "rm -rf \"$tmpPath\"" EXIT
 
     tmpFile="$tmpPath/$dstFile"