diff --git a/backend/services/data-management-service/src/main/java/com/datamate/datamanagement/application/KnowledgeItemApplicationService.java b/backend/services/data-management-service/src/main/java/com/datamate/datamanagement/application/KnowledgeItemApplicationService.java
index d98c9d8..7dc7362 100644
--- a/backend/services/data-management-service/src/main/java/com/datamate/datamanagement/application/KnowledgeItemApplicationService.java
+++ b/backend/services/data-management-service/src/main/java/com/datamate/datamanagement/application/KnowledgeItemApplicationService.java
@@ -366,12 +366,9 @@ public class KnowledgeItemApplicationService {
 
         String relativePath = knowledgeItem.getContent();
         BusinessAssert.isTrue(StringUtils.isNotBlank(relativePath), CommonErrorCode.PARAM_ERROR);
-        Path filePath = resolveKnowledgeItemStoragePath(relativePath);
-        BusinessAssert.isTrue(Files.exists(filePath) && Files.isRegularFile(filePath), CommonErrorCode.PARAM_ERROR);
-
         String previewName = StringUtils.isNotBlank(knowledgeItem.getSourceFileId())
             ? knowledgeItem.getSourceFileId()
-            : filePath.getFileName().toString();
+            : Paths.get(relativePath).getFileName().toString();
 
         if (knowledgeItemPreviewService.isOfficeDocument(previewName)) {
             KnowledgeItemPreviewService.PreviewFile previewFile = knowledgeItemPreviewService.resolveReadyPreviewFile(setId, knowledgeItem);
@@ -393,6 +390,9 @@ public class KnowledgeItemApplicationService {
             return;
         }
 
+        Path filePath = resolveKnowledgeItemStoragePath(relativePath);
+        BusinessAssert.isTrue(Files.exists(filePath) && Files.isRegularFile(filePath), CommonErrorCode.PARAM_ERROR);
+
         String contentType = null;
         try {
             contentType = Files.probeContentType(filePath);