diff --git a/java/ql/lib/semmle/code/java/os/OSCheck.qll b/java/ql/lib/semmle/code/java/os/OSCheck.qll
index f78086476dea..d43e2015705b 100644
--- a/java/ql/lib/semmle/code/java/os/OSCheck.qll
+++ b/java/ql/lib/semmle/code/java/os/OSCheck.qll
@@ -112,23 +112,26 @@ private predicate isOsFromApacheCommons(FieldAccess fa, string fieldNamePattern)
 }
 
 private class IsWindowsFromApacheCommons extends IsWindowsGuard instanceof FieldAccess {
-  IsWindowsFromApacheCommons() { isOsFromApacheCommons(this, "IS_OS_WINDOWS") }
+  IsWindowsFromApacheCommons() { isOsFromApacheCommons(this, "IS\\_OS\\_WINDOWS") }
 }
 
 private class IsSpecificWindowsVariantFromApacheCommons extends IsSpecificWindowsVariant instanceof FieldAccess {
-  IsSpecificWindowsVariantFromApacheCommons() { isOsFromApacheCommons(this, "IS_OS_WINDOWS_%") }
+  IsSpecificWindowsVariantFromApacheCommons() {
+    isOsFromApacheCommons(this, "IS\\_OS\\_WINDOWS\\_%")
+  }
 }
 
 private class IsUnixFromApacheCommons extends IsUnixGuard instanceof FieldAccess {
-  IsUnixFromApacheCommons() { isOsFromApacheCommons(this, "IS_OS_UNIX") }
+  IsUnixFromApacheCommons() { isOsFromApacheCommons(this, "IS\\_OS\\_UNIX") }
 }
 
 private class IsSpecificUnixVariantFromApacheCommons extends IsSpecificUnixVariant instanceof FieldAccess {
   IsSpecificUnixVariantFromApacheCommons() {
     isOsFromApacheCommons(this,
       [
-        "IS_OS_AIX", "IS_OS_HP_UX", "IS_OS_IRIX", "IS_OS_LINUX", "IS_OS_MAC%", "IS_OS_FREE_BSD",
-        "IS_OS_OPEN_BSD", "IS_OS_NET_BSD", "IS_OS_SOLARIS", "IS_OS_SUN_OS", "IS_OS_ZOS"
+        "IS\\_OS\\_AIX", "IS\\_OS\\_HP\\_UX", "IS\\_OS\\_IRIX", "IS\\_OS\\_LINUX", "IS\\_OS\\_MAC%",
+        "IS\\_OS\\_FREE\\_BSD", "IS\\_OS\\_OPEN\\_BSD", "IS\\_OS\\_NET\\_BSD", "IS\\_OS\\_SOLARIS",
+        "IS\\_OS\\_SUN\\_OS", "IS\\_OS\\_ZOS"
       ])
   }
 }
diff --git a/java/ql/src/Security/CWE/CWE-200/TempDirLocalInformationDisclosure.ql b/java/ql/src/Security/CWE/CWE-200/TempDirLocalInformationDisclosure.ql
index e4a4786a09a9..01d60f1062ed 100644
--- a/java/ql/src/Security/CWE/CWE-200/TempDirLocalInformationDisclosure.ql
+++ b/java/ql/src/Security/CWE/CWE-200/TempDirLocalInformationDisclosure.ql
@@ -105,23 +105,21 @@ private class FileCreateTempFileSink extends FileCreationSink {
 }
 
 /**
- * A guard that holds when the program is definitely running under some version of Windows.
+ * A sanitizer that holds when the program is definitely running under some version of Windows.
  */
-abstract private class WindowsOsBarrierGuard extends DataFlow::BarrierGuard { }
+abstract private class WindowsOsSanitizer extends DataFlow::Node { }
 
-private class IsNotUnixBarrierGuard extends WindowsOsBarrierGuard instanceof IsUnixGuard {
-  override predicate checks(Expr e, boolean branch) {
-    this.controls(e.getBasicBlock(), branch.booleanNot())
-  }
+private class IsNotUnixSanitizer extends WindowsOsSanitizer {
+  IsNotUnixSanitizer() { any(IsUnixGuard guard).controls(this.asExpr().getBasicBlock(), false) }
 }
 
-private class IsWindowsBarrierGuard extends WindowsOsBarrierGuard instanceof IsWindowsGuard {
-  override predicate checks(Expr e, boolean branch) { this.controls(e.getBasicBlock(), branch) }
+private class IsWindowsSanitizer extends WindowsOsSanitizer {
+  IsWindowsSanitizer() { any(IsWindowsGuard guard).controls(this.asExpr().getBasicBlock(), true) }
 }
 
-private class IsSpecificWindowsBarrierGuard extends WindowsOsBarrierGuard instanceof IsSpecificWindowsVariant {
-  override predicate checks(Expr e, boolean branch) {
-    branch = true and this.controls(e.getBasicBlock(), branch)
+private class IsSpecificWindowsSanitizer extends WindowsOsSanitizer {
+  IsSpecificWindowsSanitizer() {
+    any(IsSpecificWindowsVariant guard).controls(this.asExpr().getBasicBlock(), true)
   }
 }
 
@@ -155,10 +153,8 @@ private class TempDirSystemGetPropertyToCreateConfig extends TaintTracking::Conf
     exists(FilesSanitizingCreationMethodAccess sanitisingMethodAccess |
       sanitizer.asExpr() = sanitisingMethodAccess.getArgument(0)
     )
-  }
-
-  override predicate isSanitizerGuard(DataFlow::BarrierGuard guard) {
-    guard instanceof WindowsOsBarrierGuard
+    or
+    sanitizer instanceof WindowsOsSanitizer
   }
 }
 
diff --git a/java/ql/src/Security/CWE/CWE-200/TempDirUtils.qll b/java/ql/src/Security/CWE/CWE-200/TempDirUtils.qll
index a2ee4fc13d17..1984f16a58c0 100644
--- a/java/ql/src/Security/CWE/CWE-200/TempDirUtils.qll
+++ b/java/ql/src/Security/CWE/CWE-200/TempDirUtils.qll
@@ -58,7 +58,6 @@ private predicate isTaintPropagatingFileTransformation(Expr expSource, Expr expr
  * For example, `taintedFile.getCanonicalFile()` is itself tainted.
  */
 predicate isAdditionalFileTaintStep(DataFlow::Node node1, DataFlow::Node node2) {
-  isFileConstructorArgument(node1.asExpr(), node2.asExpr(), _) or
   isTaintPropagatingFileTransformation(node1.asExpr(), node2.asExpr())
 }
 
diff --git a/java/ql/src/change-notes/2022-04-06-local-temp-file-or-directory-bugfix.md b/java/ql/src/change-notes/2022-04-06-local-temp-file-or-directory-bugfix.md
new file mode 100644
index 000000000000..52cb8c5fc63b
--- /dev/null
+++ b/java/ql/src/change-notes/2022-04-06-local-temp-file-or-directory-bugfix.md
@@ -0,0 +1,4 @@
+---
+category: minorAnalysis
+---
+ * Fixed "Local information disclosure in a temporary directory" (`java/local-temp-file-or-directory-information-disclosure`) to resolve false-negatives when OS isn't properly used as logical guard.
diff --git a/java/ql/test/query-tests/security/CWE-200/semmle/tests/TempDirLocalInformationDisclosure.expected b/java/ql/test/query-tests/security/CWE-200/semmle/tests/TempDirLocalInformationDisclosure.expected
index 5d471dcd671e..0791e49c71b0 100644
--- a/java/ql/test/query-tests/security/CWE-200/semmle/tests/TempDirLocalInformationDisclosure.expected
+++ b/java/ql/test/query-tests/security/CWE-200/semmle/tests/TempDirLocalInformationDisclosure.expected
@@ -1,38 +1,26 @@
 edges
 | Files.java:10:24:10:69 | new File(...) : File | Files.java:14:37:14:43 | baseDir : File |
-| Files.java:10:24:10:69 | new File(...) : File | Files.java:15:17:15:23 | tempDir |
 | Files.java:10:33:10:68 | getProperty(...) : String | Files.java:10:24:10:69 | new File(...) : File |
-| Files.java:10:33:10:68 | getProperty(...) : String | Files.java:14:37:14:43 | baseDir : File |
-| Files.java:10:33:10:68 | getProperty(...) : String | Files.java:15:17:15:23 | tempDir |
 | Files.java:14:28:14:64 | new File(...) : File | Files.java:15:17:15:23 | tempDir |
 | Files.java:14:37:14:43 | baseDir : File | Files.java:14:28:14:64 | new File(...) : File |
 | Test.java:36:24:36:69 | new File(...) : File | Test.java:39:63:39:69 | tempDir |
 | Test.java:36:33:36:68 | getProperty(...) : String | Test.java:36:24:36:69 | new File(...) : File |
-| Test.java:36:33:36:68 | getProperty(...) : String | Test.java:39:63:39:69 | tempDir |
 | Test.java:50:29:50:94 | new File(...) : File | Test.java:53:63:53:74 | tempDirChild |
 | Test.java:50:38:50:83 | new File(...) : File | Test.java:50:29:50:94 | new File(...) : File |
-| Test.java:50:38:50:83 | new File(...) : File | Test.java:53:63:53:74 | tempDirChild |
 | Test.java:50:47:50:82 | getProperty(...) : String | Test.java:50:38:50:83 | new File(...) : File |
-| Test.java:50:47:50:82 | getProperty(...) : String | Test.java:53:63:53:74 | tempDirChild |
 | Test.java:61:24:61:69 | new File(...) : File | Test.java:64:63:64:69 | tempDir |
 | Test.java:61:33:61:68 | getProperty(...) : String | Test.java:61:24:61:69 | new File(...) : File |
-| Test.java:61:33:61:68 | getProperty(...) : String | Test.java:64:63:64:69 | tempDir |
 | Test.java:75:24:75:69 | new File(...) : File | Test.java:78:63:78:69 | tempDir |
 | Test.java:75:33:75:68 | getProperty(...) : String | Test.java:75:24:75:69 | new File(...) : File |
-| Test.java:75:33:75:68 | getProperty(...) : String | Test.java:78:63:78:69 | tempDir |
 | Test.java:110:29:110:84 | new File(...) : File | Test.java:113:9:113:20 | tempDirChild |
 | Test.java:110:38:110:73 | getProperty(...) : String | Test.java:110:29:110:84 | new File(...) : File |
-| Test.java:110:38:110:73 | getProperty(...) : String | Test.java:113:9:113:20 | tempDirChild |
 | Test.java:134:29:134:84 | new File(...) : File | Test.java:137:9:137:20 | tempDirChild |
 | Test.java:134:38:134:73 | getProperty(...) : String | Test.java:134:29:134:84 | new File(...) : File |
-| Test.java:134:38:134:73 | getProperty(...) : String | Test.java:137:9:137:20 | tempDirChild |
 | Test.java:158:29:158:88 | new File(...) : File | Test.java:159:21:159:32 | tempDirChild : File |
 | Test.java:158:38:158:73 | getProperty(...) : String | Test.java:158:29:158:88 | new File(...) : File |
-| Test.java:158:38:158:73 | getProperty(...) : String | Test.java:159:21:159:32 | tempDirChild : File |
 | Test.java:159:21:159:32 | tempDirChild : File | Test.java:159:21:159:41 | toPath(...) |
 | Test.java:187:29:187:88 | new File(...) : File | Test.java:188:21:188:32 | tempDirChild : File |
 | Test.java:187:38:187:73 | getProperty(...) : String | Test.java:187:29:187:88 | new File(...) : File |
-| Test.java:187:38:187:73 | getProperty(...) : String | Test.java:188:21:188:32 | tempDirChild : File |
 | Test.java:188:21:188:32 | tempDirChild : File | Test.java:188:21:188:41 | toPath(...) |
 | Test.java:204:29:204:104 | new File(...) : File | Test.java:204:29:204:113 | toPath(...) : Path |
 | Test.java:204:29:204:113 | toPath(...) : Path | Test.java:207:33:207:44 | tempDirChild |
@@ -42,28 +30,28 @@ edges
 | Test.java:216:38:216:73 | getProperty(...) : String | Test.java:216:29:216:102 | new File(...) : File |
 | Test.java:228:29:228:100 | new File(...) : File | Test.java:231:26:231:37 | tempDirChild : File |
 | Test.java:228:38:228:73 | getProperty(...) : String | Test.java:228:29:228:100 | new File(...) : File |
-| Test.java:228:38:228:73 | getProperty(...) : String | Test.java:231:26:231:37 | tempDirChild : File |
 | Test.java:231:26:231:37 | tempDirChild : File | Test.java:231:26:231:46 | toPath(...) |
 | Test.java:249:29:249:101 | new File(...) : File | Test.java:252:31:252:42 | tempDirChild : File |
 | Test.java:249:38:249:73 | getProperty(...) : String | Test.java:249:29:249:101 | new File(...) : File |
-| Test.java:249:38:249:73 | getProperty(...) : String | Test.java:252:31:252:42 | tempDirChild : File |
 | Test.java:252:31:252:42 | tempDirChild : File | Test.java:252:31:252:51 | toPath(...) |
 | Test.java:260:29:260:109 | new File(...) : File | Test.java:263:33:263:44 | tempDirChild : File |
 | Test.java:260:38:260:73 | getProperty(...) : String | Test.java:260:29:260:109 | new File(...) : File |
-| Test.java:260:38:260:73 | getProperty(...) : String | Test.java:263:33:263:44 | tempDirChild : File |
 | Test.java:263:33:263:44 | tempDirChild : File | Test.java:263:33:263:53 | toPath(...) |
 | Test.java:294:29:294:101 | new File(...) : File | Test.java:298:35:298:46 | tempDirChild : File |
 | Test.java:294:38:294:73 | getProperty(...) : String | Test.java:294:29:294:101 | new File(...) : File |
-| Test.java:294:38:294:73 | getProperty(...) : String | Test.java:298:35:298:46 | tempDirChild : File |
 | Test.java:298:35:298:46 | tempDirChild : File | Test.java:298:35:298:55 | toPath(...) |
 | Test.java:313:29:313:101 | new File(...) : File | Test.java:316:35:316:46 | tempDirChild : File |
 | Test.java:313:38:313:73 | getProperty(...) : String | Test.java:313:29:313:101 | new File(...) : File |
-| Test.java:313:38:313:73 | getProperty(...) : String | Test.java:316:35:316:46 | tempDirChild : File |
 | Test.java:316:35:316:46 | tempDirChild : File | Test.java:316:35:316:55 | toPath(...) |
 | Test.java:322:29:322:101 | new File(...) : File | Test.java:326:35:326:46 | tempDirChild : File |
 | Test.java:322:38:322:73 | getProperty(...) : String | Test.java:322:29:322:101 | new File(...) : File |
-| Test.java:322:38:322:73 | getProperty(...) : String | Test.java:326:35:326:46 | tempDirChild : File |
 | Test.java:326:35:326:46 | tempDirChild : File | Test.java:326:35:326:55 | toPath(...) |
+| Test.java:350:29:350:101 | new File(...) : File | Test.java:355:35:355:46 | tempDirChild : File |
+| Test.java:350:38:350:73 | getProperty(...) : String | Test.java:350:29:350:101 | new File(...) : File |
+| Test.java:355:35:355:46 | tempDirChild : File | Test.java:355:35:355:55 | toPath(...) |
+| Test.java:361:29:361:101 | new File(...) : File | Test.java:366:35:366:46 | tempDirChild : File |
+| Test.java:361:38:361:73 | getProperty(...) : String | Test.java:361:29:361:101 | new File(...) : File |
+| Test.java:366:35:366:46 | tempDirChild : File | Test.java:366:35:366:55 | toPath(...) |
 nodes
 | Files.java:10:24:10:69 | new File(...) : File | semmle.label | new File(...) : File |
 | Files.java:10:33:10:68 | getProperty(...) : String | semmle.label | getProperty(...) : String |
@@ -133,6 +121,14 @@ nodes
 | Test.java:322:38:322:73 | getProperty(...) : String | semmle.label | getProperty(...) : String |
 | Test.java:326:35:326:46 | tempDirChild : File | semmle.label | tempDirChild : File |
 | Test.java:326:35:326:55 | toPath(...) | semmle.label | toPath(...) |
+| Test.java:350:29:350:101 | new File(...) : File | semmle.label | new File(...) : File |
+| Test.java:350:38:350:73 | getProperty(...) : String | semmle.label | getProperty(...) : String |
+| Test.java:355:35:355:46 | tempDirChild : File | semmle.label | tempDirChild : File |
+| Test.java:355:35:355:55 | toPath(...) | semmle.label | toPath(...) |
+| Test.java:361:29:361:101 | new File(...) : File | semmle.label | new File(...) : File |
+| Test.java:361:38:361:73 | getProperty(...) : String | semmle.label | getProperty(...) : String |
+| Test.java:366:35:366:46 | tempDirChild : File | semmle.label | tempDirChild : File |
+| Test.java:366:35:366:55 | toPath(...) | semmle.label | toPath(...) |
 subpaths
 #select
 | Files.java:10:33:10:68 | getProperty(...) | Files.java:10:33:10:68 | getProperty(...) : String | Files.java:15:17:15:23 | tempDir | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Files.java:10:33:10:68 | getProperty(...) | system temp directory |
@@ -155,3 +151,5 @@ subpaths
 | Test.java:294:38:294:73 | getProperty(...) | Test.java:294:38:294:73 | getProperty(...) : String | Test.java:298:35:298:55 | toPath(...) | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Test.java:294:38:294:73 | getProperty(...) | system temp directory |
 | Test.java:313:38:313:73 | getProperty(...) | Test.java:313:38:313:73 | getProperty(...) : String | Test.java:316:35:316:55 | toPath(...) | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Test.java:313:38:313:73 | getProperty(...) | system temp directory |
 | Test.java:322:38:322:73 | getProperty(...) | Test.java:322:38:322:73 | getProperty(...) : String | Test.java:326:35:326:55 | toPath(...) | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Test.java:322:38:322:73 | getProperty(...) | system temp directory |
+| Test.java:350:38:350:73 | getProperty(...) | Test.java:350:38:350:73 | getProperty(...) : String | Test.java:355:35:355:55 | toPath(...) | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Test.java:350:38:350:73 | getProperty(...) | system temp directory |
+| Test.java:361:38:361:73 | getProperty(...) | Test.java:361:38:361:73 | getProperty(...) : String | Test.java:366:35:366:55 | toPath(...) | Local information disclosure vulnerability from $@ due to use of file or directory readable by other local users. | Test.java:361:38:361:73 | getProperty(...) | system temp directory |
diff --git a/java/ql/test/query-tests/security/CWE-200/semmle/tests/Test.java b/java/ql/test/query-tests/security/CWE-200/semmle/tests/Test.java
index 3ea5fe3e112f..e1ec05ac51c7 100644
--- a/java/ql/test/query-tests/security/CWE-200/semmle/tests/Test.java
+++ b/java/ql/test/query-tests/security/CWE-200/semmle/tests/Test.java
@@ -344,4 +344,26 @@ void safeBecauseInvertedFileSeperatorCheck() throws IOException {
             Files.createDirectory(tempDirChild.toPath());
         }
     }
+
+    void vulnerableBecauseFileSeparatorCheckElseCase() throws IOException {
+        // GIVEN:
+        File tempDirChild = new File(System.getProperty("java.io.tmpdir"), "/child-create-directory");
+
+        if (File.separatorChar == '\\') {
+            Files.createDirectory(tempDirChild.toPath()); // Safe
+        } else {
+            Files.createDirectory(tempDirChild.toPath()); // Vulnerable
+        }
+    }
+
+    void vulnerableBecauseInvertedFileSeperatorCheckElseCase() throws IOException {
+        // GIVEN:
+        File tempDirChild = new File(System.getProperty("java.io.tmpdir"), "/child-create-directory");
+
+        if (File.separatorChar != '/') {
+            Files.createDirectory(tempDirChild.toPath()); // Safe
+        } else {
+            Files.createDirectory(tempDirChild.toPath()); // Vulnerable
+        }
+    }
 }