diff --git a/autotests/jobtest.cpp b/autotests/jobtest.cpp
--- a/autotests/jobtest.cpp
+++ b/autotests/jobtest.cpp
@@ -78,6 +78,9 @@
     // To avoid a runtime dependency on klauncher
     qputenv("KDE_FORK_SLAVES", "yes");
 
+    // to make sure io is not too fast
+    qputenv("KIOSLAVE_FILE_ENABLE_TESTMODE", "1");
+
     s_referenceTimeStamp = QDateTime::currentDateTime().addSecs(-30);   // 30 seconds ago
 
     // Start with a clean base dir
@@ -2083,41 +2086,44 @@
 
     const QString baseDir = homeTmpDir();
     const QString srcTemplate = baseDir + QStringLiteral("testfile_XXXXXX");
-    const QString destFile = baseDir + QStringLiteral("testfile_copy_") + QString::fromLatin1(QTest::currentDataTag());
+    const QString destFile = baseDir + QStringLiteral("testfile_copy_slow_") + QString::fromLatin1(QTest::currentDataTag());
 
     QTemporaryFile f(srcTemplate);
     if (!f.open()) {
         qFatal("Couldn't open %s", qPrintable(f.fileName()));
     }
-    f.seek(9999999);
+    f.seek(999999);
     f.write("0");
     f.close();
-    QCOMPARE(f.size(), 10000000); //~10MB
+    QCOMPARE(f.size(), 1000000); //~1MB
 
     if (overwrite) {
         createTestFile(destFile);
     }
+    const QString destToCheck = (overwrite) ? destFile + QStringLiteral(".part") : destFile;
 
     KIO::JobFlag m_overwriteFlag = overwrite ? KIO::Overwrite : KIO::DefaultFlags;
     KIO::FileCopyJob *copyJob = KIO::file_copy(QUrl::fromLocalFile(f.fileName()), QUrl::fromLocalFile(destFile), -1, KIO::HideProgressInfo | m_overwriteFlag);
     copyJob->setUiDelegate(nullptr);
     QSignalSpy spyProcessedSize(copyJob, &KIO::Job::processedSize);
-    connect(copyJob, &KIO::Job::processedSize, this, [destFile, suspend, overwrite](KJob *job, qulonglong processedSize) {
+    QSignalSpy spyFinished(copyJob, &KIO::Job::finished);
+    connect(copyJob, &KIO::Job::processedSize, this, [destFile, suspend, destToCheck](KJob *job, qulonglong processedSize) {
         if (processedSize > 0) {
-            const QString destToCheck = (!overwrite) ? destFile : destFile + QStringLiteral(".part");
             QVERIFY2(QFile::exists(destToCheck), qPrintable(destToCheck));
             if (suspend) {
                 job->suspend();
             }
-            job->kill();
-            QVERIFY(!QFile::exists(destToCheck));
+            QVERIFY(job->kill());
         }
     });
+
     QVERIFY(!copyJob->exec());
     QCOMPARE(spyProcessedSize.count(), 1);
-    // Give time to the kioslave to finish copy() and warn about chown/chmod failing (because FileCopyJob::doKill removed the file)
-    // Less confusing if the warnings show here.
-    QTest::qWait(500);
-    QVERIFY(!QFile::exists(destFile));
+    QCOMPARE(spyFinished.count(), 1);
+    QCOMPARE(copyJob->error(), KIO::ERR_USER_CANCELED);
+
+    // the destination file actual deletion happens after finished() is emitted
+    // we need to give some time to the ioslave to finish the file cleaning
+    QTRY_VERIFY2(!QFile::exists(destToCheck), qPrintable(destToCheck));
 }
 
diff --git a/src/core/filecopyjob.cpp b/src/core/filecopyjob.cpp
--- a/src/core/filecopyjob.cpp
+++ b/src/core/filecopyjob.cpp
@@ -578,6 +578,12 @@
 
 bool FileCopyJob::doKill()
 {
+#ifdef Q_OS_WIN
+//TODO Use SetConsoleCtrlHandler on Windows or similar behaviour.
+// https://stackoverflow.com/questions/2007516/is-there-a-posix-sigterm-alternative-on-windows-a-gentle-kill-for-console-ap
+// https://danielkaes.wordpress.com/2009/06/04/how-to-catch-kill-events-with-python/
+// https://phabricator.kde.org/D25117#566107
+
     Q_D(FileCopyJob);
 
     // If we are interrupted in the middle of file copying,
@@ -592,7 +598,7 @@
             QFile::remove(d->m_dest.toLocalFile());
         }
     }
-
+#endif
     return Job::doKill();
 }
 
diff --git a/src/ioslaves/file/file.h b/src/ioslaves/file/file.h
--- a/src/ioslaves/file/file.h
+++ b/src/ioslaves/file/file.h
@@ -121,6 +121,8 @@
     mutable QHash<KUserId, QString> mUsercache;
     mutable QHash<KGroupId, QString> mGroupcache;
     QFile *mFile;
+
+    bool testMode = false;
 };
 
 #endif
diff --git a/src/ioslaves/file/file.cpp b/src/ioslaves/file/file.cpp
--- a/src/ioslaves/file/file.cpp
+++ b/src/ioslaves/file/file.cpp
@@ -163,6 +163,7 @@
 FileProtocol::FileProtocol(const QByteArray &pool, const QByteArray &app)
     : SlaveBase(QByteArrayLiteral("file"), pool, app), mFile(nullptr)
 {
+    testMode = !qEnvironmentVariableIsEmpty("KIOSLAVE_FILE_ENABLE_TESTMODE");
 }
 
 FileProtocol::~FileProtocol()
diff --git a/src/ioslaves/file/file_unix.cpp b/src/ioslaves/file/file_unix.cpp
--- a/src/ioslaves/file/file_unix.cpp
+++ b/src/ioslaves/file/file_unix.cpp
@@ -31,6 +31,7 @@
 #include <QDir>
 #include <qplatformdefs.h>
 #include <QStandardPaths>
+#include <QThread>
 
 #include <QDebug>
 #include <kconfiggroup.h>
@@ -311,7 +312,12 @@
     bool use_sendfile = buff_src.st_size < 0x7FFFFFFF;
 #endif
     bool existing_dest_delete_attempted = false;
-    while (1) {
+    while (!wasKilled()) {
+
+        if (testMode && dest_file.fileName().contains(QLatin1String("slow"))) {
+            QThread::usleep(500);
+        }
+
 #ifdef USE_SENDFILE
         if (use_sendfile) {
             off_t sf = processed_size;
@@ -398,6 +404,15 @@
     src_file.close();
     dest_file.close();
 
+    if (wasKilled()) {
+        qCDebug(KIO_FILE) << "Clean dest file after ioslave was killed:" << dest;
+        if (!QFile::remove(dest)) {  // don't keep partly copied file
+            execWithElevatedPrivilege(DEL, {_dest}, errno);
+        }
+        error(KIO::ERR_USER_CANCELED, dest);
+        return;
+    }
+
     if (dest_file.error() != QFile::NoError) {
         qCWarning(KIO_FILE) << "Error when closing file descriptor[2]:" << dest_file.errorString();
         error(KIO::ERR_CANNOT_WRITE, dest);