diff --git a/code/rest/dav_service.go b/code/rest/dav_service.go
index eabdfee..d49c1a6 100644
--- a/code/rest/dav_service.go
+++ b/code/rest/dav_service.go
@@ -383,7 +383,11 @@ func (this *DavService) prepareMoveCopy(
 		panic(result.BadRequest("you cannot move the root directory"))
 	}
 
-	destDirMatter = this.matterDao.CheckWithRootByPath(destinationDirPath, user)
+	destDirMatter = this.matterDao.FindWithRootByPath(destinationDirPath, user)
+	if destDirMatter == nil {
+		//throw conflict error
+		panic(result.CustomWebResult(result.CONFLICT, fmt.Sprintf("%s not exist", destinationDirPath)))
+	}
 
 	return srcMatter, destDirMatter, srcDirPath, destinationDirPath, destinationName, overwrite
 
@@ -411,6 +415,11 @@ func (this *DavService) HandleCopy(writer http.ResponseWriter, request *http.Req
 
 	fmt.Printf("COPY %s\n", subPath)
 
+	//debug point
+	if request.Header.Get("X-Litmus") == "copymove: 5 (copy_nodestcoll)" {
+		fmt.Println("stop here")
+	}
+
 	srcMatter, destDirMatter, _, _, destinationName, overwrite := this.prepareMoveCopy(writer, request, user, subPath)
 
 	//copy to the new directory
@@ -418,6 +427,14 @@ func (this *DavService) HandleCopy(writer http.ResponseWriter, request *http.Req
 
 	this.logger.Info("finish copying %s => %s", subPath, destDirMatter.Path)
 
+	if overwrite {
+		//overwrite old. set the status code 204
+		writer.WriteHeader(http.StatusNoContent)
+	} else {
+		//copy new. set the status code 201
+		writer.WriteHeader(http.StatusCreated)
+	}
+
 }
 
 //lock.
diff --git a/code/rest/matter_service.go b/code/rest/matter_service.go
index eca52cf..be0569f 100644
--- a/code/rest/matter_service.go
+++ b/code/rest/matter_service.go
@@ -528,7 +528,8 @@ func (this *MatterService) handleOverwrite(request *http.Request, user *User, de
 			//delete.
 			this.Delete(request, destMatter, user)
 		} else {
-			panic(result.BadRequestI18n(request, i18n.MatterExist, destMatter.Path))
+			//throw precondition failed. (RFC4918:10.6)
+			panic(result.CustomWebResult(result.PRECONDITION_FAILED, fmt.Sprintf("%s exists", destMatter.Path)))
 		}
 	}
 
diff --git a/code/tool/result/web_result.go b/code/tool/result/web_result.go
index 13ed050..96e7e46 100644
--- a/code/tool/result/web_result.go
+++ b/code/tool/result/web_result.go
@@ -33,6 +33,7 @@ var (
 	NOT_FOUND              = &CodeWrapper{Code: "NOT_FOUND", HttpStatus: http.StatusNotFound, Description: "404 not found"}
 	METHOD_NOT_ALLOWED     = &CodeWrapper{Code: "METHOD_NOT_ALLOWED", HttpStatus: http.StatusMethodNotAllowed, Description: "405 method not allowed"}
 	CONFLICT               = &CodeWrapper{Code: "CONFLICT", HttpStatus: http.StatusConflict, Description: "409 conflict"}
+	PRECONDITION_FAILED    = &CodeWrapper{Code: "PRECONDITION_FAILED", HttpStatus: http.StatusPreconditionFailed, Description: "412 precondition failed"}
 	UNSUPPORTED_MEDIA_TYPE = &CodeWrapper{Code: "UNSUPPORTED_MEDIA_TYPE", HttpStatus: http.StatusUnsupportedMediaType, Description: "415 conflict"}
 	RANGE_NOT_SATISFIABLE  = &CodeWrapper{Code: "RANGE_NOT_SATISFIABLE", HttpStatus: http.StatusRequestedRangeNotSatisfiable, Description: "range not satisfiable"}
 	NOT_INSTALLED          = &CodeWrapper{Code: "NOT_INSTALLED", HttpStatus: http.StatusInternalServerError, Description: "application not installed"}
@@ -61,6 +62,8 @@ func FetchHttpStatus(code string) int {
 		return METHOD_NOT_ALLOWED.HttpStatus
 	} else if code == CONFLICT.Code {
 		return CONFLICT.HttpStatus
+	} else if code == PRECONDITION_FAILED.Code {
+		return PRECONDITION_FAILED.HttpStatus
 	} else if code == UNSUPPORTED_MEDIA_TYPE.Code {
 		return UNSUPPORTED_MEDIA_TYPE.HttpStatus
 	} else if code == RANGE_NOT_SATISFIABLE.Code {
diff --git a/code/tool/util/util_file.go b/code/tool/util/util_file.go
index 1dca8af..e398953 100644
--- a/code/tool/util/util_file.go
+++ b/code/tool/util/util_file.go
@@ -128,7 +128,11 @@ func GetFilenameOfPath(fullPath string) string {
 func DeleteEmptyDir(dirPath string) bool {
 	dir, err := ioutil.ReadDir(dirPath)
 	if err != nil {
-		panic(result.BadRequest("occur error while reading %s %s", dirPath, err.Error()))
+		if strings.Contains(err.Error(), "The system cannot find") {
+			return false
+		} else {
+			panic(result.BadRequest("occur error while reading %s %s", dirPath, err.Error()))
+		}
 	}
 	if len(dir) == 0 {
 		//empty dir