frontend/src/components/FileList.tsx

@@ -16,8 +16,9 @@ import {
   DialogContent,
   DialogActions,
   Typography,
+  Tooltip,
 } from '@mui/material';
-import { Download as DownloadIcon, Delete as DeleteIcon } from '@mui/icons-material';
+import { Download as DownloadIcon, Delete as DeleteIcon, Error as ErrorIcon } from '@mui/icons-material';
 import { File, FileStatus } from '../types/file';
 import { api } from '../services/api';
 
@@ -172,6 +173,50 @@ const FileList: React.FC<FileListProps> = ({ files, onFileStatusChange }) => {
                     color={getStatusColor(file.status) as any}
                     size="small"
                   />
+                  {file.status === FileStatus.FAILED && file.error_message && (
+                    <div style={{ marginTop: '4px' }}>
+                      <Tooltip 
+                        title={file.error_message}
+                        placement="top-start"
+                        arrow
+                        sx={{ maxWidth: '400px' }}
+                      >
+                        <div 
+                          style={{ 
+                            display: 'flex', 
+                            alignItems: 'flex-start', 
+                            gap: '4px',
+                            padding: '4px 8px',
+                            backgroundColor: '#ffebee',
+                            borderRadius: '4px',
+                            border: '1px solid #ffcdd2'
+                          }}
+                        >
+                          <ErrorIcon 
+                            color="error" 
+                            sx={{ fontSize: '16px', marginTop: '1px', flexShrink: 0 }} 
+                          />
+                          <Typography
+                            variant="caption"
+                            color="error"
+                            sx={{
+                              display: 'block',
+                              wordBreak: 'break-word',
+                              maxWidth: '300px',
+                              lineHeight: '1.2',
+                              cursor: 'help',
+                              fontWeight: 500
+                            }}
+                          >
+                            {file.error_message.length > 50 
+                              ? `${file.error_message.substring(0, 50)}...` 
+                              : file.error_message
+                            }
+                          </Typography>
+                        </div>
+                      </Tooltip>
+                    </div>
+                  )}
                 </TableCell>
                 <TableCell>
                   {new Date(file.created_at).toLocaleString()}