diff --git a/kotlinx-coroutines-core/common/test/JobTest.kt b/kotlinx-coroutines-core/common/test/JobTest.kt
index f009c7e55d..38895830b6 100644
--- a/kotlinx-coroutines-core/common/test/JobTest.kt
+++ b/kotlinx-coroutines-core/common/test/JobTest.kt
@@ -103,11 +103,11 @@ class JobTest : TestBase() {
         }
         assertTrue(job.isActive)
         for (i in 0 until n) assertEquals(0, fireCount[i])
-        val tryCancel = Try { job.cancel() }
+        val cancelResult = runCatching { job.cancel() }
         assertTrue(!job.isActive)
         for (i in 0 until n) assertEquals(1, fireCount[i])
-        assertTrue(tryCancel.exception is CompletionHandlerException)
-        assertTrue(tryCancel.exception!!.cause is TestException)
+        assertTrue(cancelResult.exceptionOrNull() is CompletionHandlerException)
+        assertTrue(cancelResult.exceptionOrNull()!!.cause is TestException)
     }
 
     @Test
diff --git a/kotlinx-coroutines-core/common/test/TestBase.common.kt b/kotlinx-coroutines-core/common/test/TestBase.common.kt
index 8b7024a60a..06e71b45b5 100644
--- a/kotlinx-coroutines-core/common/test/TestBase.common.kt
+++ b/kotlinx-coroutines-core/common/test/TestBase.common.kt
@@ -104,3 +104,5 @@ class BadClass {
     override fun hashCode(): Int = error("hashCode")
     override fun toString(): String = error("toString")
 }
+
+public expect val isJavaAndWindows: Boolean
diff --git a/kotlinx-coroutines-core/common/test/Try.kt b/kotlinx-coroutines-core/common/test/Try.kt
deleted file mode 100644
index 194ea4bafa..0000000000
--- a/kotlinx-coroutines-core/common/test/Try.kt
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Copyright 2016-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
- */
-
-package kotlinx.coroutines
-
-public class Try<out T> private constructor(private val _value: Any?) {
-    private class Fail(val exception: Throwable) {
-        override fun toString(): String = "Failure[$exception]"
-    }
-
-    public companion object {
-        public operator fun <T> invoke(block: () -> T): Try<T> =
-                try {
-                    Success(block())
-                } catch(e: Throwable) {
-                    Failure<T>(e)
-                }
-        public fun <T> Success(value: T) = Try<T>(value)
-        public fun <T> Failure(exception: Throwable) = Try<T>(Fail(exception))
-    }
-
-    @Suppress("UNCHECKED_CAST")
-    public val value: T get() = if (_value is Fail) throw _value.exception else _value as T
-
-    public val exception: Throwable? get() = (_value as? Fail)?.exception
-
-    override fun toString(): String = _value.toString()
-}
diff --git a/kotlinx-coroutines-core/common/test/WithTimeoutOrNullDurationTest.kt b/kotlinx-coroutines-core/common/test/WithTimeoutOrNullDurationTest.kt
index 92dba7b32d..1f9ad46f47 100644
--- a/kotlinx-coroutines-core/common/test/WithTimeoutOrNullDurationTest.kt
+++ b/kotlinx-coroutines-core/common/test/WithTimeoutOrNullDurationTest.kt
@@ -131,6 +131,7 @@ class WithTimeoutOrNullDurationTest : TestBase() {
 
     @Test
     fun testOuterTimeout() = runTest {
+        if (isJavaAndWindows) return@runTest
         var counter = 0
         val result = withTimeoutOrNull(320.milliseconds) {
             while (true) {
diff --git a/kotlinx-coroutines-core/common/test/WithTimeoutOrNullTest.kt b/kotlinx-coroutines-core/common/test/WithTimeoutOrNullTest.kt
index ee896c9bf0..5ab8ae7df9 100644
--- a/kotlinx-coroutines-core/common/test/WithTimeoutOrNullTest.kt
+++ b/kotlinx-coroutines-core/common/test/WithTimeoutOrNullTest.kt
@@ -128,6 +128,7 @@ class WithTimeoutOrNullTest : TestBase() {
 
     @Test
     fun testOuterTimeout() = runTest {
+        if (isJavaAndWindows) return@runTest
         var counter = 0
         val result = withTimeoutOrNull(320) {
             while (true) {
diff --git a/kotlinx-coroutines-core/js/test/TestBase.kt b/kotlinx-coroutines-core/js/test/TestBase.kt
index c930c20030..f0e3a2dc7a 100644
--- a/kotlinx-coroutines-core/js/test/TestBase.kt
+++ b/kotlinx-coroutines-core/js/test/TestBase.kt
@@ -138,3 +138,5 @@ public actual open class TestBase actual constructor() {
 
 private fun <T> Promise<T>.finally(block: () -> Unit): Promise<T> =
     then(onFulfilled = { value -> block(); value }, onRejected = { ex -> block(); throw ex })
+
+public actual val isJavaAndWindows: Boolean get() = false
diff --git a/kotlinx-coroutines-core/jvm/test/TestBase.kt b/kotlinx-coroutines-core/jvm/test/TestBase.kt
index ce94d33acc..6a013fa1da 100644
--- a/kotlinx-coroutines-core/jvm/test/TestBase.kt
+++ b/kotlinx-coroutines-core/jvm/test/TestBase.kt
@@ -254,3 +254,10 @@ public actual open class TestBase(private var disableOutCheck: Boolean)  {
 
     protected suspend fun currentDispatcher() = coroutineContext[ContinuationInterceptor]!!
 }
+
+/*
+ * We ignore tests that test **real** non-virtualized tests with time on Windows, because
+ * our CI Windows is virtualized itself (oh, the irony) and its clock resolution is dozens of ms,
+ * which makes such tests flaky.
+ */
+public actual val isJavaAndWindows: Boolean = System.getProperty("os.name")!!.contains("Windows")
diff --git a/kotlinx-coroutines-core/native/test/TestBase.kt b/kotlinx-coroutines-core/native/test/TestBase.kt
index 6fef4752a8..d7dfeeaeba 100644
--- a/kotlinx-coroutines-core/native/test/TestBase.kt
+++ b/kotlinx-coroutines-core/native/test/TestBase.kt
@@ -107,3 +107,5 @@ public actual open class TestBase actual constructor() {
             error("Too few unhandled exceptions $exCount, expected ${unhandled.size}")
     }
 }
+
+public actual val isJavaAndWindows: Boolean get() = false