diff --git a/.github/workflows/__language-aliases.yml b/.github/workflows/__language-aliases.yml
index d64abe876d..a4cdb034bf 100644
--- a/.github/workflows/__language-aliases.yml
+++ b/.github/workflows/__language-aliases.yml
@@ -60,12 +60,12 @@ jobs:
           setup-kotlin: 'true'
       - uses: ./../action/init
         with:
-          languages: C#,java-kotlin,swift,typescript
+          languages: C#,java-kotlin,typescript
           tools: ${{ steps.prepare-test.outputs.tools-url }}
 
       - name: 'Check languages'
         run: |
-          expected_languages="csharp,java,swift,javascript"
+          expected_languages="csharp,java,javascript"
           actual_languages=$(jq -r '.languages | join(",")' "$RUNNER_TEMP"/config)
 
           if [ "$expected_languages" != "$actual_languages" ]; then
diff --git a/lib/analyze-action-post.js b/lib/analyze-action-post.js
index c9a434400f..32196392d0 100644
--- a/lib/analyze-action-post.js
+++ b/lib/analyze-action-post.js
@@ -161960,6 +161960,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/analyze-action.js b/lib/analyze-action.js
index 969d0f015a..2fabf45d96 100644
--- a/lib/analyze-action.js
+++ b/lib/analyze-action.js
@@ -107434,6 +107434,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/autobuild-action.js b/lib/autobuild-action.js
index cdcceeb25d..a0accec339 100644
--- a/lib/autobuild-action.js
+++ b/lib/autobuild-action.js
@@ -104016,6 +104016,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/init-action-post.js b/lib/init-action-post.js
index 1128ae8278..ddd0308c31 100644
--- a/lib/init-action-post.js
+++ b/lib/init-action-post.js
@@ -165315,6 +165315,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/init-action.js b/lib/init-action.js
index 86b8fb3a16..e9afbeece8 100644
--- a/lib/init-action.js
+++ b/lib/init-action.js
@@ -107837,6 +107837,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
@@ -110293,6 +110299,11 @@ async function run(startedAt) {
       enableFileCoverageInformation: fileCoverageResult.enabled,
       logger
     });
+    if (config.languages.includes("swift" /* swift */) && process.platform === "linux") {
+      throw new ConfigurationError(
+        `Swift analysis on Ubuntu runner images is no longer supported. Please migrate to a macOS runner.`
+      );
+    }
     if (repositoryPropertiesResult.isFailure()) {
       addNoLanguageDiagnostic(
         config,
@@ -110377,11 +110388,6 @@ async function run(startedAt) {
         "Passing the GOFLAGS env parameter to the init action is deprecated. Please move this to the analyze action."
       );
     }
-    if (config.languages.includes("swift" /* swift */) && process.platform === "linux") {
-      logger.warning(
-        `Swift analysis on Ubuntu runner images is no longer supported. Please migrate to a macOS runner if this affects you.`
-      );
-    }
     if (config.languages.includes("go" /* go */) && process.platform === "linux") {
       try {
         const goBinaryPath = await io6.which("go", true);
diff --git a/lib/resolve-environment-action.js b/lib/resolve-environment-action.js
index 8efaa0b031..6d6e29821f 100644
--- a/lib/resolve-environment-action.js
+++ b/lib/resolve-environment-action.js
@@ -104015,6 +104015,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/setup-codeql-action.js b/lib/setup-codeql-action.js
index 3f54f6f0c0..73541a3b87 100644
--- a/lib/setup-codeql-action.js
+++ b/lib/setup-codeql-action.js
@@ -105062,6 +105062,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/start-proxy-action-post.js b/lib/start-proxy-action-post.js
index 688eeb733b..25d0f40c6b 100644
--- a/lib/start-proxy-action-post.js
+++ b/lib/start-proxy-action-post.js
@@ -162127,6 +162127,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/upload-lib.js b/lib/upload-lib.js
index 3a26187564..fc84b64a64 100644
--- a/lib/upload-lib.js
+++ b/lib/upload-lib.js
@@ -107067,6 +107067,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/upload-sarif-action-post.js b/lib/upload-sarif-action-post.js
index 2585c49ad9..d2c4866978 100644
--- a/lib/upload-sarif-action-post.js
+++ b/lib/upload-sarif-action-post.js
@@ -161791,6 +161791,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/lib/upload-sarif-action.js b/lib/upload-sarif-action.js
index b78507de3f..ac8ee8eac8 100644
--- a/lib/upload-sarif-action.js
+++ b/lib/upload-sarif-action.js
@@ -108505,6 +108505,12 @@ var cliErrorsConfig = {
       )
     ]
   },
+  ["SwiftIncompatibleOs" /* SwiftIncompatibleOs */]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS")
+    ]
+  },
   ["UnsupportedBuildMode" /* UnsupportedBuildMode */]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/pr-checks/checks/language-aliases.yml b/pr-checks/checks/language-aliases.yml
index 8fcde341d0..b83dd5d0fa 100644
--- a/pr-checks/checks/language-aliases.yml
+++ b/pr-checks/checks/language-aliases.yml
@@ -5,12 +5,12 @@ versions:
 steps:
   - uses: ./../action/init
     with:
-      languages: C#,java-kotlin,swift,typescript
+      languages: C#,java-kotlin,typescript
       tools: ${{ steps.prepare-test.outputs.tools-url }}
 
   - name: "Check languages"
     run: |
-      expected_languages="csharp,java,swift,javascript"
+      expected_languages="csharp,java,javascript"
       actual_languages=$(jq -r '.languages | join(",")' "$RUNNER_TEMP"/config)
 
       if [ "$expected_languages" != "$actual_languages" ]; then
diff --git a/src/cli-errors.test.ts b/src/cli-errors.test.ts
index 7a3ed892ba..9e2d7dc799 100644
--- a/src/cli-errors.test.ts
+++ b/src/cli-errors.test.ts
@@ -299,6 +299,20 @@ test("wrapCliConfigurationError - swift build failed", (t) => {
   t.true(wrappedError instanceof ConfigurationError);
 });
 
+test("wrapCliConfigurationError - swift incompatible os", (t) => {
+  const commandError = new CommandInvocationError(
+    "codeql",
+    ["swift/tools/autobuild.sh"],
+    1,
+    "2026-04-01 18:35:00 EST ERRO [extractor/main] [incompatible-os] Currently, Swift analysis is only supported on macOS. (IncompatibleOs.cpp:26)",
+  );
+  const cliError = new CliError(commandError);
+
+  const wrappedError = wrapCliConfigurationError(cliError);
+
+  t.true(wrappedError instanceof ConfigurationError);
+});
+
 test("wrapCliConfigurationError - pack cannot be found", (t) => {
   const commandError = new CommandInvocationError(
     "codeql",
diff --git a/src/cli-errors.ts b/src/cli-errors.ts
index 5aba268cab..84ec1aa4e6 100644
--- a/src/cli-errors.ts
+++ b/src/cli-errors.ts
@@ -144,6 +144,7 @@ export enum CliConfigErrorCategory {
   OutOfMemoryOrDisk = "OutOfMemoryOrDisk",
   PackCannotBeFound = "PackCannotBeFound",
   PackMissingAuth = "PackMissingAuth",
+  SwiftIncompatibleOs = "SwiftIncompatibleOs",
   SwiftBuildFailed = "SwiftBuildFailed",
   UnsupportedBuildMode = "UnsupportedBuildMode",
 }
@@ -281,6 +282,12 @@ const cliErrorsConfig: Record<CliConfigErrorCategory, CliErrorConfiguration> = {
       ),
     ],
   },
+  [CliConfigErrorCategory.SwiftIncompatibleOs]: {
+    cliErrorMessageCandidates: [
+      new RegExp("\\[incompatible-os\\]"),
+      new RegExp("Swift analysis is only supported on macOS"),
+    ],
+  },
   [CliConfigErrorCategory.UnsupportedBuildMode]: {
     cliErrorMessageCandidates: [
       new RegExp(
diff --git a/src/init-action.ts b/src/init-action.ts
index 70d5d79ce5..fd24fa6f85 100644
--- a/src/init-action.ts
+++ b/src/init-action.ts
@@ -389,6 +389,15 @@ async function run(startedAt: Date) {
       logger,
     });
 
+    if (
+      config.languages.includes(KnownLanguage.swift) &&
+      process.platform === "linux"
+    ) {
+      throw new ConfigurationError(
+        `Swift analysis on Ubuntu runner images is no longer supported. Please migrate to a macOS runner.`,
+      );
+    }
+
     if (repositoryPropertiesResult.isFailure()) {
       addNoLanguageDiagnostic(
         config,
@@ -499,15 +508,6 @@ async function run(startedAt: Date) {
       );
     }
 
-    if (
-      config.languages.includes(KnownLanguage.swift) &&
-      process.platform === "linux"
-    ) {
-      logger.warning(
-        `Swift analysis on Ubuntu runner images is no longer supported. Please migrate to a macOS runner if this affects you.`,
-      );
-    }
-
     if (
       config.languages.includes(KnownLanguage.go) &&
       process.platform === "linux"