diff --git a/weed/admin/handlers/file_browser_handlers.go b/weed/admin/handlers/file_browser_handlers.go
index bafaa60c3..eeb8e2d85 100644
--- a/weed/admin/handlers/file_browser_handlers.go
+++ b/weed/admin/handlers/file_browser_handlers.go
@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -21,6 +22,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/admin/view/layout"
 	"github.com/seaweedfs/seaweedfs/weed/glog"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
+	"github.com/seaweedfs/seaweedfs/weed/util"
 	"github.com/seaweedfs/seaweedfs/weed/util/http/client"
 )
 
@@ -267,8 +269,12 @@ func (h *FileBrowserHandlers) UploadFile(c *gin.Context) {
 			continue
 		}
 
-		// Create full path for the file
-		fullPath := filepath.Join(currentPath, fileName)
+		// Normalize Windows-style backslashes to forward slashes
+		fileName = util.CleanWindowsPath(fileName)
+
+		// Create full path for the file using path.Join for URL path semantics
+		// path.Join handles double slashes and is not OS-specific like filepath.Join
+		fullPath := path.Join(currentPath, fileName)
 		if !strings.HasPrefix(fullPath, "/") {
 			fullPath = "/" + fullPath
 		}
@@ -349,8 +355,10 @@ func (h *FileBrowserHandlers) uploadFileToFiler(filePath string, fileHeader *mul
 	var body bytes.Buffer
 	writer := multipart.NewWriter(&body)
 
-	// Create form file field
-	part, err := writer.CreateFormFile("file", fileHeader.Filename)
+	// Create form file field with normalized base filename
+	// Use path.Base (not filepath.Base) since cleanFilePath uses URL path semantics
+	baseFileName := path.Base(cleanFilePath)
+	part, err := writer.CreateFormFile("file", baseFileName)
 	if err != nil {
 		return fmt.Errorf("failed to create form file: %w", err)
 	}
@@ -452,8 +460,12 @@ func (h *FileBrowserHandlers) validateAndCleanFilePath(filePath string) (string,
 		return "", fmt.Errorf("file path cannot be empty")
 	}
 
+	// Normalize Windows-style backslashes to forward slashes
+	filePath = util.CleanWindowsPath(filePath)
+
 	// Clean the path to remove any .. or . components
-	cleanPath := filepath.Clean(filePath)
+	// Use path.Clean (not filepath.Clean) since this is a URL path
+	cleanPath := path.Clean(filePath)
 
 	// Ensure the path starts with /
 	if !strings.HasPrefix(cleanPath, "/") {
diff --git a/weed/storage/needle/needle_parse_upload.go b/weed/storage/needle/needle_parse_upload.go
index 89708303d..6fadd80d6 100644
--- a/weed/storage/needle/needle_parse_upload.go
+++ b/weed/storage/needle/needle_parse_upload.go
@@ -128,7 +128,7 @@ func parseUpload(r *http.Request, sizeLimit int64, pu *ParsedUpload) (e error) {
 
 		pu.FileName = part.FileName()
 		if pu.FileName != "" {
-			pu.FileName = path.Base(pu.FileName)
+			pu.FileName = util.CleanWindowsPathBase(pu.FileName)
 		}
 
 		dataSize, e = pu.bytesBuffer.ReadFrom(io.LimitReader(part, sizeLimit+1))
@@ -169,7 +169,7 @@ func parseUpload(r *http.Request, sizeLimit int64, pu *ParsedUpload) (e error) {
 
 				// update
 				pu.Data = pu.bytesBuffer.Bytes()
-				pu.FileName = path.Base(fName)
+				pu.FileName = util.CleanWindowsPathBase(fName)
 				contentType = part.Header.Get("Content-Type")
 				part = part2
 				break
@@ -207,7 +207,7 @@ func parseUpload(r *http.Request, sizeLimit int64, pu *ParsedUpload) (e error) {
 		}
 
 		if pu.FileName != "" {
-			pu.FileName = path.Base(pu.FileName)
+			pu.FileName = util.CleanWindowsPathBase(pu.FileName)
 		} else {
 			pu.FileName = path.Base(r.URL.Path)
 		}
diff --git a/weed/util/fullpath.go b/weed/util/fullpath.go
index c145919da..b485cae0d 100644
--- a/weed/util/fullpath.go
+++ b/weed/util/fullpath.go
@@ -1,6 +1,7 @@
 package util
 
 import (
+	"path"
 	"path/filepath"
 	"strings"
 )
@@ -85,3 +86,15 @@ func StringSplit(separatedValues string, sep string) []string {
 	}
 	return strings.Split(separatedValues, sep)
 }
+
+// CleanWindowsPath normalizes Windows-style backslashes to forward slashes.
+// This handles paths from Windows clients where paths use backslashes.
+func CleanWindowsPath(p string) string {
+	return strings.ReplaceAll(p, "\\", "/")
+}
+
+// CleanWindowsPathBase normalizes Windows-style backslashes to forward slashes
+// and returns the base name of the path.
+func CleanWindowsPathBase(p string) string {
+	return path.Base(strings.ReplaceAll(p, "\\", "/"))
+}