diff --git a/pkgs/applications/audio/renoise/default.nix b/pkgs/applications/audio/renoise/default.nix
index d3462ecc6ad5..a56d43876fb0 100644
--- a/pkgs/applications/audio/renoise/default.nix
+++ b/pkgs/applications/audio/renoise/default.nix
@@ -39,7 +39,7 @@ in stdenv.mkDerivation rec {
     releasePath
   else
     let
-      platform = platforms.${stdenv.system};
+      platform = platforms.${stdenv.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
       urlVersion = lib.replaceStrings [ "." ] [ "_" ] version;
     in fetchurl {
       url =
diff --git a/pkgs/applications/gis/udig/default.nix b/pkgs/applications/gis/udig/default.nix
index 8510918d4cab..264445336cd3 100644
--- a/pkgs/applications/gis/udig/default.nix
+++ b/pkgs/applications/gis/udig/default.nix
@@ -13,7 +13,7 @@ let
       hash = "sha256-Ihk3InHB3/tEYRqH2ozhokz2GN8Gfig5DJkO/8P1LJs=";
     };
   };
-  src = srcs.${stdenv.hostPlatform.system};
+  src = srcs.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
 
   meta = with lib; {
     description = "User-friendly Desktop Internet GIS";
diff --git a/pkgs/applications/graphics/sane/backends/brscan4/default.nix b/pkgs/applications/graphics/sane/backends/brscan4/default.nix
index ec8efcc27c2a..c15b3033a265 100644
--- a/pkgs/applications/graphics/sane/backends/brscan4/default.nix
+++ b/pkgs/applications/graphics/sane/backends/brscan4/default.nix
@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
       url = "https://download.brother.com/welcome/dlf006645/${pname}-${version}.amd64.deb";
       sha256 = "sha256-Gpr5456MCNpyam3g2qPo7S3aEZFMaUGR8bu7YmRY8xk=";
     };
-  }."${stdenv.hostPlatform.system}";
+  }."${stdenv.hostPlatform.system}" or (throw "unsupported system ${stdenv.hostPlatform.system}");
 
   unpackPhase = ''
     ar x $src
diff --git a/pkgs/applications/misc/1password-gui/default.nix b/pkgs/applications/misc/1password-gui/default.nix
index 33a8328d688b..5f8b7c9068ac 100644
--- a/pkgs/applications/misc/1password-gui/default.nix
+++ b/pkgs/applications/misc/1password-gui/default.nix
@@ -51,7 +51,7 @@ let
   };
 
   src = fetchurl {
-    inherit (sources.${channel}.${stdenv.system}) url hash;
+    inherit (sources.${channel}.${stdenv.system} or (throw "unsupported system ${stdenv.hostPlatform.system}")) url hash;
   };
 
   meta = with lib; {
diff --git a/pkgs/applications/networking/cluster/hadoop/default.nix b/pkgs/applications/networking/cluster/hadoop/default.nix
index d5bae9ad885b..5f44e39d008c 100644
--- a/pkgs/applications/networking/cluster/hadoop/default.nix
+++ b/pkgs/applications/networking/cluster/hadoop/default.nix
@@ -35,7 +35,7 @@ let
       src = fetchurl {
         url = "mirror://apache/hadoop/common/hadoop-${finalAttrs.version}/hadoop-${finalAttrs.version}"
               + optionalString stdenv.isAarch64 "-aarch64" + ".tar.gz";
-        inherit (platformAttrs.${stdenv.system}) hash;
+        inherit (platformAttrs.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}")) hash;
       };
       doCheck = true;
 
diff --git a/pkgs/applications/networking/instant-messengers/discord/default.nix b/pkgs/applications/networking/instant-messengers/discord/default.nix
index 58bab558db74..f9604c2ce166 100644
--- a/pkgs/applications/networking/instant-messengers/discord/default.nix
+++ b/pkgs/applications/networking/instant-messengers/discord/default.nix
@@ -52,7 +52,7 @@ let
     };
     aarch64-darwin = x86_64-darwin;
   };
-  src = srcs.${stdenv.hostPlatform.system}.${branch};
+  src = srcs.${stdenv.hostPlatform.system}.${branch} or (throw "${stdenv.hostPlatform.system} not supported on ${branch}");
 
   meta = with lib; {
     description = "All-in-one cross-platform voice and text chat for gamers";
diff --git a/pkgs/applications/science/electronics/picoscope/default.nix b/pkgs/applications/science/electronics/picoscope/default.nix
index c7242117b68c..3aa5cb22aa52 100644
--- a/pkgs/applications/science/electronics/picoscope/default.nix
+++ b/pkgs/applications/science/electronics/picoscope/default.nix
@@ -49,7 +49,7 @@ let
   # If we don't have a platform available, put a dummy version here, so at
   # least evaluation succeeds.
   sources =
-    (lib.importJSON ./sources.json).${stdenv.system} or { picoscope.version = "unknown"; };
+    (lib.importJSON ./sources.json).${stdenv.system} or (throw "unsupported system ${stdenv.system}");
 
   scopePkg = name:
     { url, version, sha256 }:
diff --git a/pkgs/applications/version-management/radicle-upstream/default.nix b/pkgs/applications/version-management/radicle-upstream/default.nix
index 97fec6257dd1..69c960ed78e8 100644
--- a/pkgs/applications/version-management/radicle-upstream/default.nix
+++ b/pkgs/applications/version-management/radicle-upstream/default.nix
@@ -15,7 +15,7 @@ let
       sha256 = "sha256-EuWGbn6qggi8/9Rci8iaXfuVKE+QXb1BHEYDvotR/q4=";
     };
   };
-  src = srcs.${stdenv.hostPlatform.system};
+  src = srcs.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
 
   contents = appimageTools.extract { inherit name src; };
 
diff --git a/pkgs/applications/virtualization/firecracker/default.nix b/pkgs/applications/virtualization/firecracker/default.nix
index d9bab2169623..2c3ec6c9a75b 100644
--- a/pkgs/applications/virtualization/firecracker/default.nix
+++ b/pkgs/applications/virtualization/firecracker/default.nix
@@ -13,7 +13,7 @@ let
 
   dlbin = sha256: fetchurl {
     url = "${baseurl}/v${version}/firecracker-v${version}-${suffix}.tgz";
-    sha256 = sha256."${stdenv.hostPlatform.system}";
+    sha256 = sha256."${stdenv.hostPlatform.system}"or (throw "unsupported system ${stdenv.hostPlatform.system}");
   };
 
 in
diff --git a/pkgs/development/compilers/oraclejdk/jdk-linux-base.nix b/pkgs/development/compilers/oraclejdk/jdk-linux-base.nix
index 40681faae8ae..d03419e96570 100644
--- a/pkgs/development/compilers/oraclejdk/jdk-linux-base.nix
+++ b/pkgs/development/compilers/oraclejdk/jdk-linux-base.nix
@@ -80,7 +80,7 @@ let result = stdenv.mkDerivation rec {
     in requireFile {
       name = "jdk-${productVersion}u${patchVersion}-${platformName}.tar.gz";
       url = "http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html";
-      sha256 = sha256.${stdenv.hostPlatform.system};
+      sha256 = sha256.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
     };
 
   nativeBuildInputs = [ file makeWrapper ]
diff --git a/pkgs/development/compilers/temurin-bin/jdk-darwin-base.nix b/pkgs/development/compilers/temurin-bin/jdk-darwin-base.nix
index 14871813273d..8f6831a7907c 100644
--- a/pkgs/development/compilers/temurin-bin/jdk-darwin-base.nix
+++ b/pkgs/development/compilers/temurin-bin/jdk-darwin-base.nix
@@ -24,7 +24,7 @@ let
       sourcePerArch.${cpuName}.version or (throw "unsupported CPU ${cpuName}");
 
     src = fetchurl {
-      inherit (sourcePerArch.${cpuName}) url sha256;
+      inherit (sourcePerArch.${cpuName} or (throw "unsupported system ${stdenv.hostPlatform.system}")) url sha256;
     };
 
     # See: https://github.com/NixOS/patchelf/issues/10
diff --git a/pkgs/development/libraries/libcef/default.nix b/pkgs/development/libraries/libcef/default.nix
index d6d098110af8..ce83c3c22cd4 100644
--- a/pkgs/development/libraries/libcef/default.nix
+++ b/pkgs/development/libraries/libcef/default.nix
@@ -73,7 +73,7 @@ let
   platforms."aarch64-linux".sha256 = "16sbfk599h96wcsmpbxlwsvq0n1pssmm8dpwmjsqfrn1464dvs68";
   platforms."x86_64-linux".sha256 = "1wa4nv28saz96kar9svdarfz6c4rnbcqz0rqxzl9zclnhfzhqdiw";
 
-  platformInfo = builtins.getAttr stdenv.hostPlatform.system platforms;
+  platformInfo = platforms.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
 in
 stdenv.mkDerivation rec {
   pname = "cef-binary";
diff --git a/pkgs/servers/meteor/default.nix b/pkgs/servers/meteor/default.nix
index 0ce2189568cb..7830d309b082 100644
--- a/pkgs/servers/meteor/default.nix
+++ b/pkgs/servers/meteor/default.nix
@@ -20,7 +20,7 @@ in
 stdenv.mkDerivation {
   inherit version;
   pname = "meteor";
-  src = srcs.${system};
+  src = srcs.${system} or (throw "unsupported system ${system}");
 
   #dontStrip = true;
 
diff --git a/pkgs/tools/archivers/rar/default.nix b/pkgs/tools/archivers/rar/default.nix
index 3799afd736ef..fabcfde887e0 100644
--- a/pkgs/tools/archivers/rar/default.nix
+++ b/pkgs/tools/archivers/rar/default.nix
@@ -37,7 +37,7 @@ stdenv.mkDerivation {
   pname = "rar";
   inherit version;
 
-  src = fetchurl (srcs.${stdenv.hostPlatform.system});
+  src = fetchurl (srcs.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}"));
 
   dontBuild = true;
 
diff --git a/pkgs/tools/misc/geekbench/5.nix b/pkgs/tools/misc/geekbench/5.nix
index 7784b3632a73..49efe2ea0bf9 100644
--- a/pkgs/tools/misc/geekbench/5.nix
+++ b/pkgs/tools/misc/geekbench/5.nix
@@ -26,7 +26,7 @@ stdenv.mkDerivation {
   inherit version;
   pname = "geekbench";
 
-  src = fetchurl (sources.${stdenv.system});
+  src = fetchurl (sources.${stdenv.system} or (throw "unsupported system ${stdenv.hostPlatform.system}"));
 
   dontConfigure = true;
   dontBuild = true;
diff --git a/pkgs/tools/misc/geekbench/6.nix b/pkgs/tools/misc/geekbench/6.nix
index 4ac5f1d0e49a..373d93dc193c 100644
--- a/pkgs/tools/misc/geekbench/6.nix
+++ b/pkgs/tools/misc/geekbench/6.nix
@@ -27,7 +27,7 @@ stdenv.mkDerivation {
   inherit version;
   pname = "geekbench";
 
-  src = fetchurl (sources.${stdenv.system});
+  src = fetchurl (sources.${stdenv.system} or (throw "unsupported system ${stdenv.hostPlatform.system}"));
 
   dontConfigure = true;
   dontBuild = true;
diff --git a/pkgs/tools/misc/hakuneko/default.nix b/pkgs/tools/misc/hakuneko/default.nix
index 0ad8c5907a70..0359da603ccb 100644
--- a/pkgs/tools/misc/hakuneko/default.nix
+++ b/pkgs/tools/misc/hakuneko/default.nix
@@ -36,7 +36,7 @@ stdenv.mkDerivation rec {
       url = "https://github.com/manga-download/hakuneko/releases/download/v${version}/hakuneko-desktop_${version}_linux_i386.deb";
       sha256 = "32017d26bafffaaf0a83dd6954d3926557014af4022a972371169c56c0e3d98b";
     };
-  }."${stdenv.hostPlatform.system}";
+  }."${stdenv.hostPlatform.system}" or (throw "unsupported system ${stdenv.hostPlatform.system}");
 
   dontBuild = true;
   dontConfigure = true;
diff --git a/pkgs/tools/security/sonar-scanner-cli/default.nix b/pkgs/tools/security/sonar-scanner-cli/default.nix
index 553019299ba7..b97a2bc3a105 100644
--- a/pkgs/tools/security/sonar-scanner-cli/default.nix
+++ b/pkgs/tools/security/sonar-scanner-cli/default.nix
@@ -19,7 +19,7 @@ in stdenv.mkDerivation rec {
   inherit version;
   pname = "sonar-scanner-cli";
 
-  src = fetchurl sonarScannerArchPackage.${stdenv.hostPlatform.system};
+  src = fetchurl sonarScannerArchPackage.${stdenv.hostPlatform.system} or (throw "unsupported system ${stdenv.hostPlatform.system}");
 
   nativeBuildInputs = [ unzip ];