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 7dc7362..a254c3d 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
@@ -333,7 +333,7 @@ public class KnowledgeItemApplicationService {
 
         String relativePath = knowledgeItem.getContent();
         BusinessAssert.isTrue(StringUtils.isNotBlank(relativePath), CommonErrorCode.PARAM_ERROR);
-        Path filePath = resolveKnowledgeItemStoragePath(relativePath);
+        Path filePath = resolveKnowledgeItemStoragePathWithFallback(relativePath);
         BusinessAssert.isTrue(Files.exists(filePath) && Files.isRegularFile(filePath), CommonErrorCode.PARAM_ERROR);
 
         String downloadName = StringUtils.isNotBlank(knowledgeItem.getSourceFileId())
@@ -390,7 +390,7 @@ public class KnowledgeItemApplicationService {
             return;
         }
 
-        Path filePath = resolveKnowledgeItemStoragePath(relativePath);
+        Path filePath = resolveKnowledgeItemStoragePathWithFallback(relativePath);
         BusinessAssert.isTrue(Files.exists(filePath) && Files.isRegularFile(filePath), CommonErrorCode.PARAM_ERROR);
 
         String contentType = null;
@@ -532,6 +532,86 @@ public class KnowledgeItemApplicationService {
         return target;
     }
 
+    private Path resolveKnowledgeItemStoragePathWithFallback(String relativePath) {
+        BusinessAssert.isTrue(StringUtils.isNotBlank(relativePath), CommonErrorCode.PARAM_ERROR);
+        String normalizedInput = relativePath.replace("\\", PATH_SEPARATOR).trim();
+        Path root = resolveUploadRootPath();
+        java.util.LinkedHashSet<Path> candidates = new java.util.LinkedHashSet<>();
+
+        Path inputPath = Paths.get(normalizedInput.replace(PATH_SEPARATOR, File.separator));
+        if (inputPath.isAbsolute()) {
+            Path normalizedAbsolute = inputPath.toAbsolutePath().normalize();
+            if (normalizedAbsolute.startsWith(root)) {
+                candidates.add(normalizedAbsolute);
+            }
+            String segmentRelativePath = extractRelativePathFromSegment(normalizedInput, KNOWLEDGE_ITEM_UPLOAD_DIR);
+            if (StringUtils.isNotBlank(segmentRelativePath)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, segmentRelativePath));
+            }
+            BusinessAssert.isTrue(!candidates.isEmpty(), CommonErrorCode.PARAM_ERROR);
+        } else {
+            String normalizedRelative = normalizeRelativePathValue(normalizedInput);
+            if (StringUtils.isNotBlank(normalizedRelative)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, normalizedRelative));
+            }
+            String segmentRelativePath = extractRelativePathFromSegment(normalizedInput, KNOWLEDGE_ITEM_UPLOAD_DIR);
+            if (StringUtils.isNotBlank(segmentRelativePath)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, segmentRelativePath));
+            }
+            if (StringUtils.isNotBlank(normalizedRelative)
+                    && !normalizedRelative.startsWith(KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR)
+                    && !normalizedRelative.equals(KNOWLEDGE_ITEM_UPLOAD_DIR)) {
+                candidates.add(buildKnowledgeItemStoragePath(root, KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR + normalizedRelative));
+            }
+        }
+
+        if (root.getFileName() != null && KNOWLEDGE_ITEM_UPLOAD_DIR.equals(root.getFileName().toString())) {
+            String normalizedRelative = normalizeRelativePathValue(normalizedInput);
+            if (StringUtils.isNotBlank(normalizedRelative)
+                    && normalizedRelative.startsWith(KNOWLEDGE_ITEM_UPLOAD_DIR + PATH_SEPARATOR)) {
+                String withoutPrefix = normalizedRelative.substring(KNOWLEDGE_ITEM_UPLOAD_DIR.length() + PATH_SEPARATOR.length());
+                if (StringUtils.isNotBlank(withoutPrefix)) {
+                    candidates.add(buildKnowledgeItemStoragePath(root, withoutPrefix));
+                }
+            }
+        }
+
+        Path fallback = null;
+        for (Path candidate : candidates) {
+            if (fallback == null) {
+                fallback = candidate;
+            }
+            if (Files.exists(candidate) && Files.isRegularFile(candidate)) {
+                return candidate;
+            }
+        }
+        BusinessAssert.notNull(fallback, CommonErrorCode.PARAM_ERROR);
+        return fallback;
+    }
+
+    private Path buildKnowledgeItemStoragePath(Path root, String relativePath) {
+        String normalizedRelativePath = StringUtils.defaultString(relativePath).replace(PATH_SEPARATOR, File.separator);
+        Path target = root.resolve(normalizedRelativePath).toAbsolutePath().normalize();
+        BusinessAssert.isTrue(target.startsWith(root), CommonErrorCode.PARAM_ERROR);
+        return target;
+    }
+
+    private String extractRelativePathFromSegment(String rawPath, String segment) {
+        if (StringUtils.isBlank(rawPath) || StringUtils.isBlank(segment)) {
+            return null;
+        }
+        String normalized = rawPath.replace("\\", PATH_SEPARATOR).trim();
+        while (normalized.startsWith(PATH_SEPARATOR)) {
+            normalized = normalized.substring(1);
+        }
+        String segmentPrefix = segment + PATH_SEPARATOR;
+        int index = normalized.indexOf(segmentPrefix);
+        if (index < 0) {
+            return segment.equals(normalized) ? segment : null;
+        }
+        return normalizeRelativePathValue(normalized.substring(index));
+    }
+
     private KnowledgeItemSearchResponse normalizeSearchResponse(KnowledgeItemSearchResponse item) {
         BusinessAssert.notNull(item, CommonErrorCode.PARAM_ERROR);
         if (item.getSourceType() == KnowledgeSourceType.FILE_UPLOAD) {