diff --git a/autotests/jobtest.h b/autotests/jobtest.h
--- a/autotests/jobtest.h
+++ b/autotests/jobtest.h
@@ -45,6 +45,7 @@
     void storedPutIODeviceFastDevice();
     void storedPutIODeviceSlowDevice();
     void storedPutIODeviceSlowDeviceBigChunk();
+    void fileSlaveCrash();
     void copyFileToSamePartition();
     void copyDirectoryToSamePartition();
     void copyDirectoryToExistingDirectory();
diff --git a/autotests/jobtest.cpp b/autotests/jobtest.cpp
--- a/autotests/jobtest.cpp
+++ b/autotests/jobtest.cpp
@@ -418,6 +418,57 @@
     QVERIFY(!spyPercent.isEmpty());
 }
 
+void JobTest::fileSlaveCrash()
+{
+    const QString filePath = homeTmpDir() + "fileFromHome";
+    const QUrl u = QUrl::fromLocalFile(filePath);
+    const QByteArray putDataContents(300000, 'K'); // Make sure the 300000 is bigger than MAX_READ_BUF_SIZE
+
+    QBuffer putDataBuffer;
+    QVERIFY(putDataBuffer.open(QIODevice::ReadWrite));
+
+    QBuffer putDataBuffer2;
+    QVERIFY(putDataBuffer2.open(QIODevice::ReadWrite));
+
+    KIO::StoredTransferJob *job = KIO::storedPut(&putDataBuffer, u, 0600, KIO::Overwrite | KIO::HideProgressInfo);
+    job->setAsyncDataEnabled(true);
+
+    bool job1Finished = false;
+    bool job2Finished = false;
+    int job2ErrorStatus = 0;
+
+    connect(job, &KJob::finished, [&job1Finished] {
+        job1Finished = true;
+    });
+
+    QTimer::singleShot(200, this, [&putDataBuffer, &putDataBuffer2, putDataContents, &u, &job2Finished, &job2ErrorStatus]() {
+        putDataBuffer.write(putDataContents);
+        putDataBuffer.seek(0);
+
+        KIO::StoredTransferJob *job2 = KIO::storedPut(&putDataBuffer2, u, 0600, KIO::HideProgressInfo);
+        job2->setAsyncDataEnabled(true);
+
+        putDataBuffer2.write(putDataContents);
+        putDataBuffer2.seek(0);
+
+        connect(job2, &KJob::finished, [&putDataBuffer2, &job2Finished, job2, &job2ErrorStatus] {
+            putDataBuffer2.readyRead();
+            job2Finished = true;
+            job2ErrorStatus = job2->error();
+        });
+    });
+
+    // Simulate the transfer is done
+    QTimer::singleShot(400, this, [&putDataBuffer, &putDataBuffer2](){
+        putDataBuffer.readChannelFinished();
+        putDataBuffer2.readChannelFinished();
+    });
+
+    QTRY_VERIFY(job1Finished);
+    QTRY_VERIFY(job2Finished);
+    QCOMPARE(job2ErrorStatus, KIO::ERR_FILE_ALREADY_EXIST);
+}
+
 ////
 
 void JobTest::copyLocalFile(const QString &src, const QString &dest)
diff --git a/src/core/slavebase.cpp b/src/core/slavebase.cpp
--- a/src/core/slavebase.cpp
+++ b/src/core/slavebase.cpp
@@ -1030,7 +1030,7 @@
         if (isSubCommand(cmd)) {
             dispatch(cmd, data);
         } else {
-            qFatal("Fatal Error: Got cmd %d, while waiting for an answer!", cmd);
+            qFatal("Fatal Error: Got cmd %d, while waiting for an answer. Expected: %d, %d!", cmd, expected1, expected2);
         }
     }
 }
diff --git a/src/core/storedtransferjob.cpp b/src/core/storedtransferjob.cpp
--- a/src/core/storedtransferjob.cpp
+++ b/src/core/storedtransferjob.cpp
@@ -20,6 +20,8 @@
 
 #include "storedtransferjob.h"
 #include "job_p.h"
+#include "slave.h"
+
 #include <kconfig.h>
 #include <kconfiggroup.h>
 #include <kurlauthorized.h>
@@ -93,6 +95,11 @@
             SLOT(slotStoredData(KIO::Job*,QByteArray)));
     connect(this, SIGNAL(dataReq(KIO::Job*,QByteArray&)),
             SLOT(slotStoredDataReq(KIO::Job*,QByteArray&)));
+    connect(this, &TransferJob::canResume, [&dd](KIO::Job*, KIO::filesize_t offset) {
+        if (offset != 0) {
+            dd.m_slave->sendResumeAnswer(false);
+        }
+    });
 }
 
 StoredTransferJob::~StoredTransferJob()
diff --git a/src/core/transferjob.cpp b/src/core/transferjob.cpp
--- a/src/core/transferjob.cpp
+++ b/src/core/transferjob.cpp
@@ -324,8 +324,6 @@
                                 q, SLOT(slotIODeviceClosedBeforeStart()));
             if (m_closedBeforeStart) {
                 QMetaObject::invokeMethod(q, "slotIODeviceClosed", Qt::QueuedConnection);
-            } else if (m_outgoingDataSource->bytesAvailable() > 0) {
-                QMetaObject::invokeMethod(q, "slotDataReqFromDevice", Qt::QueuedConnection);
             }
         } else {
             q->connect(slave, SIGNAL(dataReq()),