diff --git a/src/hal/filesystem/linux/file_provider_linux.c b/src/hal/filesystem/linux/file_provider_linux.c
index b807319c..05b1689e 100644
--- a/src/hal/filesystem/linux/file_provider_linux.c
+++ b/src/hal/filesystem/linux/file_provider_linux.c
@@ -58,6 +58,12 @@ FileSystem_readFile(FileHandle handle, uint8_t* buffer, int maxSize)
     return fread(buffer, maxSize, 1, (FILE*) handle);
 }
 
+int
+FileSystem_writeFile(FileHandle handle, uint8_t* buffer, int size)
+{
+    return fwrite(buffer, size, 1, (FILE*) handle);
+}
+
 void
 FileSystem_closeFile(FileHandle handle)
 {
diff --git a/src/hal/filesystem/win32/file_provider_win32.c b/src/hal/filesystem/win32/file_provider_win32.c
index 21511289..2f531e1d 100644
--- a/src/hal/filesystem/win32/file_provider_win32.c
+++ b/src/hal/filesystem/win32/file_provider_win32.c
@@ -64,6 +64,12 @@ FileSystem_readFile(FileHandle handle, uint8_t* buffer, int maxSize)
     return fread(buffer, maxSize, 1, (FILE*) handle);
 }
 
+int
+FileSystem_writeFile(FileHandle handle, uint8_t* buffer, int size)
+{
+    return fwrite(buffer, size, 1, (FILE*) handle);
+}
+
 void
 FileSystem_closeFile(FileHandle handle)
 {
diff --git a/src/hal/inc/hal_filesystem.h b/src/hal/inc/hal_filesystem.h
index f18f6745..4248810a 100644
--- a/src/hal/inc/hal_filesystem.h
+++ b/src/hal/inc/hal_filesystem.h
@@ -63,7 +63,7 @@ FileSystem_openFile(char* pathName, bool readWrite);
  *
  * This function will read the next block of the file. The maximum number of bytes to read
  * is given. A call to this function will move the file position by the number of bytes read.
- * If the file position reaches the end of file then subseqeuent calls of this function shall
+ * If the file position reaches the end of file then subsequent calls of this function shall
  * return 0.
  *
  * \param handle the file handle to identify the file
@@ -75,6 +75,18 @@ FileSystem_openFile(char* pathName, bool readWrite);
 int
 FileSystem_readFile(FileHandle handle, uint8_t* buffer, int maxSize);
 
+/**
+ * \brief write to an open file
+ *
+ * \param handle the file handle to identify the file
+ * \param buffer the buffer with the data to write
+ * \param size the number of bytes to write
+ *
+ * \return the number of bytes actually written
+ */
+int
+FileSystem_writeFile(FileHandle handle, uint8_t* buffer, int size);
+
 /**
  * \brief close an open file
  *
diff --git a/src/mms/iso_mms/client/mms_client_connection.c b/src/mms/iso_mms/client/mms_client_connection.c
index 70ea8841..36775725 100644
--- a/src/mms/iso_mms/client/mms_client_connection.c
+++ b/src/mms/iso_mms/client/mms_client_connection.c
@@ -736,7 +736,8 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 #if (MMS_OBTAIN_FILE_SERVICE == 1)
     else if (tag == 0xa0) {
 
-        printf("MMS_CLIENT: received confirmed request PDU (size=%i)\n", payload->size);
+        if (DEBUG_MMS_CLIENT)
+            printf("MMS_CLIENT: received confirmed request PDU (size=%i)\n", payload->size);
 
         // TODO handle confirmed request PDU only when obtainFile service is enabled
         // TODO extract function
@@ -761,20 +762,14 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 
             bufPos = BerDecoder_decodeLength(buf, &length, bufPos, payload->size);
 
-          //  printf("tag:%02x len:%i\n", tag, length);
-
-//            if (bufPos < 0)  {
-//              mmsServer_writeMmsRejectPdu(&invokeId, MMS_ERROR_REJECT_UNRECOGNIZED_SERVICE, response);
-//                return;
-//            }
-
             if (extendedTag) {
                 switch(tag) {
 
 #if (MMS_FILE_SERVICE == 1)
                 case 0x48: /* file-open-request */
                     {
-                        printf("MMS_CLIENT: received file-open-request\n");
+                        if (DEBUG_MMS_CLIENT)
+                            printf("MMS_CLIENT: received file-open-request\n");
 
                         ByteBuffer* response = IsoClientConnection_allocateTransmitBuffer(self->isoClient);
 
@@ -788,7 +783,8 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 
                 case 0x49: /* file-read-request */
                     {
-                        printf("MMS_CLIENT: received file-read-request\n");
+                        if (DEBUG_MMS_CLIENT)
+                            printf("MMS_CLIENT: received file-read-request\n");
 
                         ByteBuffer* response = IsoClientConnection_allocateTransmitBuffer(self->isoClient);
 
@@ -802,7 +798,8 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 
                 case 0x4a: /* file-close-request */
                     {
-                        printf("MMS_CLIENT: received file-close-request\n");
+                        if (DEBUG_MMS_CLIENT)
+                            printf("MMS_CLIENT: received file-close-request\n");
 
                         ByteBuffer* response = IsoClientConnection_allocateTransmitBuffer(self->isoClient);
 
@@ -817,8 +814,9 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 
                 default:
                    // mmsServer_writeMmsRejectPdu(&invokeId, MMS_ERROR_REJECT_UNRECOGNIZED_SERVICE, response);
+                    if (DEBUG_MMS_CLIENT)
+                        printf("MMS_CLIENT: unexpected message from server!\n");
 
-                    printf("MMS_CLIENT: unexpected message from server!\n");
                     IsoClientConnection_releaseReceiveBuffer(self->isoClient);
 
                     break;
@@ -836,8 +834,10 @@ mmsIsoCallback(IsoIndication indication, void* parameter, ByteBuffer* payload)
 
                 default:
                   //  mmsServer_writeMmsRejectPdu(&invokeId, MMS_ERROR_REJECT_UNRECOGNIZED_SERVICE, response);
-                    printf("MMS_CLIENT: unexpected message from server!\n");
-                                        IsoClientConnection_releaseReceiveBuffer(self->isoClient);
+                    if (DEBUG_MMS_CLIENT)
+                        printf("MMS_CLIENT: unexpected message from server!\n");
+
+                    IsoClientConnection_releaseReceiveBuffer(self->isoClient);
 
                     goto exit_with_error;
 
@@ -2087,8 +2087,6 @@ MmsConnection_obtainFile(MmsConnection self, MmsError* mmsError, const char* sou
 
     uint32_t invokeId = getNextInvokeId(self);
 
-    //TODO enable file service
-
     mmsClient_createObtainFileRequest(invokeId, payload, sourceFile, destinationFile);
 
     ByteBuffer* responseMessage = sendRequestAndWaitForResponse(self, invokeId, payload);
diff --git a/src/mms/iso_mms/client/mms_client_files.c b/src/mms/iso_mms/client/mms_client_files.c
index d1c1a6c3..38dff428 100644
--- a/src/mms/iso_mms/client/mms_client_files.c
+++ b/src/mms/iso_mms/client/mms_client_files.c
@@ -96,8 +96,6 @@ openFile(char* fileName, bool readWrite)
 
     createExtendedFilename(extendedFileName, fileName);
 
-    printf("open file %s\n", extendedFileName);
-
     return FileSystem_openFile(extendedFileName, readWrite);
 }
 
@@ -222,7 +220,7 @@ mmsClient_handleFileReadRequest(
     MmsFileReadStateMachine* frsm = getFrsm(connection, frsmId);
 
     if (frsm != NULL)
-        mmsMsg_createFileReadResponse(connection, invokeId, response, frsm);
+        mmsMsg_createFileReadResponse(connection->parameters.maxPduSize, invokeId, response, frsm);
     else
         mmsServer_createServiceErrorPdu(invokeId, response, MMS_ERROR_FILE_OTHER);
 }
diff --git a/src/mms/iso_mms/server/mms_file_service.c b/src/mms/iso_mms/server/mms_file_service.c
index 77ff3033..7c5b63ba 100644
--- a/src/mms/iso_mms/server/mms_file_service.c
+++ b/src/mms/iso_mms/server/mms_file_service.c
@@ -376,34 +376,25 @@ createObtainFileResponse(uint32_t invokeId, ByteBuffer* response)
     createNullResponseExtendedTag(invokeId, response, 0x2e);
 }
 
-
-//#define MMS_FILE_UPLOAD_STATE_COMPLETE 11
-
 void
 mmsServer_fileUploadTask(MmsServer self, MmsObtainFileTask task)
 {
-    //send response message
-
-    /*
-     * states:
-     * 0 - no state / not used
-     * 1 -
-     * 2 - file open sent
-     * 3 - file read sent
-     * 4 - file close sent
-     *
-     */
-    printf("mmsServer_fileUploadTask (%p) state=%i\n", task, task->state);
-
     switch (task->state) {
-        case MMS_FILE_UPLOAD_STATE_NOT_USED: /* state: not-used */
+
+        case MMS_FILE_UPLOAD_STATE_NOT_USED:
             break;
 
         case MMS_FILE_UPLOAD_STATE_FILE_OPEN_SENT:
             {
                 if (Hal_getTimeInMs() > task->nextTimeout) {
-                    printf("MMS_SERVER: file open timeout!\n");
-                    task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_RESPONSE;
+
+                    if (DEBUG_MMS_SERVER)
+                        printf("MMS_SERVER: file open timeout!\n");
+
+                    task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_SOURCE;
+
+                    FileSystem_closeFile(task->fileHandle);
+                    deleteFile(task->destinationFilename);
                 }
             }
             break;
@@ -430,8 +421,14 @@ mmsServer_fileUploadTask(MmsServer self, MmsObtainFileTask task)
         case MMS_FILE_UPLOAD_STATE_FILE_READ_SENT:
 
             if (Hal_getTimeInMs() > task->nextTimeout) {
-                printf("MMS_SERVER: file read timeout!\n");
-                task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_RESPONSE;
+
+                if (DEBUG_MMS_SERVER)
+                    printf("MMS_SERVER: file read timeout!\n");
+
+                task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_SOURCE;
+
+                FileSystem_closeFile(task->fileHandle);
+                deleteFile(task->destinationFilename);
             }
 
             break;
@@ -457,8 +454,14 @@ mmsServer_fileUploadTask(MmsServer self, MmsObtainFileTask task)
         case MMS_FILE_UPLOAD_STATE_FILE_CLOSE_SENT:
 
             if (Hal_getTimeInMs() > task->nextTimeout) {
-                printf("MMS_SERVER: file close timeout!\n");
-                task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_RESPONSE;
+
+                if (DEBUG_MMS_SERVER)
+                    printf("MMS_SERVER: file close timeout!\n");
+
+                task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_SOURCE;
+
+                FileSystem_closeFile(task->fileHandle);
+                deleteFile(task->destinationFilename);
             }
 
             break;
@@ -473,7 +476,15 @@ mmsServer_fileUploadTask(MmsServer self, MmsObtainFileTask task)
 
             break;
 
+        case MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_DESTINATION:
+
+            //TODO send ObtainFileError
+            printf("MMS_SERVER: ObtainFile service: failed to create local file\n");
+
 
+            task->state = MMS_FILE_UPLOAD_STATE_NOT_USED;
+
+            break;
 
         case MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_RESPONSE:
             {
@@ -550,29 +561,39 @@ mmsServer_handleObtainFileRequest(
 
         //TODO check if destination file already exists. If exists return error message
 
-        printf("Download file %s from client to local file %s...\n", sourceFilename, destinationFilename);
+        if (DEBUG_MMS_SERVER)
+            printf("MMS_SERVER: Start download file %s from client to local file %s...\n", sourceFilename, destinationFilename);
 
         MmsObtainFileTask task = MmsServer_getObtainFileTask(connection->server);
 
         if (task != NULL) {
 
-            /* send file open request */
-            task->lastRequestInvokeId = MmsServerConnection_getNextRequestInvokeId(connection);
-            task->connection = connection;
+            FileHandle fileHandle = openFile(destinationFilename, true);
 
-            strcpy(task->destinationFilename, destinationFilename);
+            if (fileHandle == NULL) {
+                task->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_DESTINATION;
+            }
+            else {
+                /* send file open request */
+                task->lastRequestInvokeId = MmsServerConnection_getNextRequestInvokeId(connection);
+                task->connection = connection;
+                task->fileHandle = fileHandle;
+                task->obtainFileRequestInvokeId = invokeId;
 
-            ByteBuffer* request = MmsServer_reserveTransmitBuffer(connection->server);
+                strcpy(task->destinationFilename, destinationFilename);
 
-            mmsClient_createFileOpenRequest(task->lastRequestInvokeId, request, sourceFilename, 0);
+                ByteBuffer* request = MmsServer_reserveTransmitBuffer(connection->server);
 
-            IsoConnection_sendMessage(task->connection->isoConnection, request, false);
+                mmsClient_createFileOpenRequest(task->lastRequestInvokeId, request, sourceFilename, 0);
 
-            MmsServer_releaseTransmitBuffer(connection->server);
+                IsoConnection_sendMessage(task->connection->isoConnection, request, false);
 
-            task->nextTimeout = Hal_getTimeInMs() + 2000; /* timeout 2000 ms */
+                MmsServer_releaseTransmitBuffer(connection->server);
 
-            task->state = MMS_FILE_UPLOAD_STATE_FILE_OPEN_SENT;
+                task->nextTimeout = Hal_getTimeInMs() + 2000; /* timeout 2000 ms */
+
+                task->state = MMS_FILE_UPLOAD_STATE_FILE_OPEN_SENT;
+            }
         }
         else
             goto exit_unavailable;
diff --git a/src/mms/iso_mms/server/mms_server_connection.c b/src/mms/iso_mms/server/mms_server_connection.c
index 92d5f189..3b5dccee 100644
--- a/src/mms/iso_mms/server/mms_server_connection.c
+++ b/src/mms/iso_mms/server/mms_server_connection.c
@@ -291,8 +291,10 @@ mmsFileReadHandler(void* parameter, int32_t frsmId, uint8_t* buffer, uint32_t by
 {
     MmsObtainFileTask task = (MmsObtainFileTask) parameter;
 
-    printf("  FILE %i received %i bytes\n", frsmId, bytesReceived);
-    //TODO write data to file
+    if (DEBUG_MMS_SERVER)
+        printf("MMS_SERVER:  FILE %i received %i bytes\n", frsmId, bytesReceived);
+
+    FileSystem_writeFile(task->fileHandle, buffer, bytesReceived);
 }
 
 static void
@@ -328,7 +330,9 @@ handleConfirmedResponsePdu(
 
 #if (MMS_FILE_SERVICE == 1)
             case 0x48: /* file-open-response */
-                printf("MMS_SERVER: received file-open-response\n");
+
+                if (DEBUG_MMS_SERVER)
+                    printf("MMS_SERVER: received file-open-response\n");
 
                 {
                     MmsObtainFileTask fileTask = getUploadTaskByInvokeId(self->server, invokeId);
@@ -338,26 +342,30 @@ handleConfirmedResponsePdu(
                     int32_t frmsId;
 
                         if (mmsMsg_parseFileOpenResponse(buffer, startBufPos, maxBufPos, &frmsId, NULL, NULL)) {
-                            printf("MMS_SERVER: received file-open-response with frmsId=%i\n", frmsId);
-
                             fileTask->frmsId = frmsId;
                             fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_FILE_READ;
                         }
                         else {
-                            printf("MMS_SERVER: error parsing file-open-response\n");
+                            if (DEBUG_MMS_SERVER)
+                                printf("MMS_SERVER: error parsing file-open-response\n");
                             fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_SOURCE;
                         }
                     }
-                    else
-                        printf("MMS_SERVER: unexpected file-open-response\n");
+                    else {
+                        /* ignore */
+
+                        if (DEBUG_MMS_SERVER)
+                            printf("MMS_SERVER: unexpected file-open-response\n");
+                    }
                 }
 
                 break;
 
             case 0x49: /* file-read-response */
-                printf("MMS_SERVER: received file-read-response\n");
-
                 {
+                    if (DEBUG_MMS_SERVER)
+                        printf("MMS_SERVER: received file-read-response\n");
+
                     MmsObtainFileTask fileTask = getUploadTaskByInvokeId(self->server, invokeId);
 
                     if (fileTask != NULL) {
@@ -366,42 +374,47 @@ handleConfirmedResponsePdu(
 
                         if (mmsMsg_parseFileReadResponse(buffer, startBufPos, maxBufPos, fileTask->frmsId, &moreFollows, mmsFileReadHandler, (void*) fileTask)) {
 
-                            printf("MMS_SERVER: received file data\n");
-
                             if (moreFollows) {
                                 fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_FILE_READ;
                             }
                             else {
-
-                                //TODO close local file
-
                                 fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_FILE_CLOSE;
                             }
                         }
                         else {
                             fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_ERROR_SOURCE;
-                            printf("MMS_SERVER: error parsing file-read-response\n");
+
+                            if (DEBUG_MMS_SERVER)
+                                printf("MMS_SERVER: error parsing file-read-response\n");
                         }
                     }
-                    else
-                        printf("MMS_SERVER: unexpected file-read-response\n");
+                    else {
+                        /* ignore */
+
+                        if (DEBUG_MMS_SERVER)
+                            printf("MMS_SERVER: unexpected file-read-response\n");
+                    }
                 }
 
                 break;
 
             case 0x4a: /* file-close-response */
                 {
-
-                    printf("MMS_SERVER: received file-close-response\n");
-
+                    if (DEBUG_MMS_SERVER)
+                        printf("MMS_SERVER: received file-close-response\n");
 
                     MmsObtainFileTask fileTask = getUploadTaskByInvokeId(self->server, invokeId);
 
                     if (fileTask != NULL) {
+                        FileSystem_closeFile(fileTask->fileHandle);
                         fileTask->state = MMS_FILE_UPLOAD_STATE_SEND_OBTAIN_FILE_RESPONSE;
                     }
-                    else
-                       printf("MMS_SERVER: unexpected file-close-response\n");
+                    else {
+                        /* ignore */
+
+                        if (DEBUG_MMS_SERVER)
+                            printf("MMS_SERVER: unexpected file-close-response\n");
+                    }
                 }
                 break;
 #endif /* MMS_FILE_SERVICE == 1 */
diff --git a/src/vs/libiec61850-wo-goose.def b/src/vs/libiec61850-wo-goose.def
index c658a995..c8c5be1d 100644
--- a/src/vs/libiec61850-wo-goose.def
+++ b/src/vs/libiec61850-wo-goose.def
@@ -554,3 +554,4 @@ EXPORTS
     MmsServer_installObtainFileHandler
     MmsServer_installGetFileCompleteHandler
     MmsServer_handleBackgroundTasks
+    FileSystem_writeFile
diff --git a/src/vs/libiec61850.def b/src/vs/libiec61850.def
index 1d59bc29..f0e70d8f 100644
--- a/src/vs/libiec61850.def
+++ b/src/vs/libiec61850.def
@@ -632,3 +632,4 @@ EXPORTS
     MmsServer_installObtainFileHandler
 	MmsServer_installGetFileCompleteHandler
     MmsServer_handleBackgroundTasks
+    FileSystem_writeFile