Lightroom - fichier et photo catalogue

Hi,

Images are stored in an external drive.

I tried the link you mentioned : works for some pictures but not others.

When I identify the right image/ file in the external drive this is the answer I get " Le fichier 'nom du cfichier'  est associé à une autre photo du catalogue. Ce fichier ne  peut être associé qu'à une photo"

Below is the System info in the Help menu 

Please clarify what i have to do so thta it works

OC Degen

Version Lightroom Classic: 9.1 [ 201911291132-64cf80b4 ]
Licence: Creative Cloud
Paramètre de langue: fr-FR
Système d'exploitation : Mac OS 10
Version : 10.14.6 [18G1012]
Architecture de l'application : x64
Nombre de processeurs logiques: 6
Vitesse du processeur : 3,7 Ghz
Mémoire intégrée : 8 192,0 Mo
Mémoire réelle disponible pour Lightroom : 8 192,0 Mo
Mémoire réelle utilisée par Lightroom : 783,2 Mo (9,5%)
Mémoire virtuelle utilisée par Lightroom : 5 697,8 Mo
Taille de la mémoire cache : 261,7Mo
Version interne de Camera Raw: 12.1 [ 351 ]
Nombre maximal de liens utilisé par Camera Raw : 4
Optimisation SIMD de Camera Raw : SSE2,AVX,AVX2
Mémoire virtuelle de Camera Raw: 617Mo / 4095Mo (15%)
Mémoire réelle de Camera Raw: 618Mo / 8192Mo (7%)
Affichages : 1) 5120x2880

Informations relatives au processeur graphique :
Metal: AMD Radeon Pro 580X

Dossier de l'application : /Applications/Adobe Lightroom Classic
Chemin d'accès à la bibliothèque : /Users/oliviercharlesdegen/Desktop/Lightroom Catalog.lrcat
Dossier des paramètres : /Users/oliviercharlesdegen/Library/Application Support/Adobe/Lightroom

Modules installés :
1) Adobe Stock
2) Facebook
3) Flickr
4) Module externe d'importateur Aperture/iPhoto
5) Module externe de prise de vue en mode connecté Nikon

Marqueurs Config.lua: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: Sortie intégrée
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 44100
Build: 12.1x4
CoreImage: true
GL_ACCUM_ALPHA_BITS: 0
GL_ACCUM_BLUE_BITS: 0
GL_ACCUM_GREEN_BITS: 0
GL_ACCUM_RED_BITS: 0
GL_ALPHA_BITS: 8
GL_BLUE_BITS: 8
GL_DEPTH_BITS: 24
GL_GREEN_BITS: 8
GL_MAX_3D_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_SIZE: 16384
GL_MAX_TEXTURE_UNITS: 8
GL_MAX_VIEWPORT_DIMS: 16384,16384
GL_RED_BITS: 8
GL_RENDERER: AMD Radeon Pro 580X OpenGL Engine
GL_SHADING_LANGUAGE_VERSION: 1.20
GL_STENCIL_BITS: 8
GL_VENDOR: ATI Technologies Inc.
GL_VERSION: 2.1 ATI-2.11.21
OGLEnabled: true
GL_EXTENSIONS: GL_ARB_color_buffer_float GL_ARB_depth_buffer_float GL_ARB_depth_clamp GL_ARB_depth_texture GL_ARB_draw_buffers GL_ARB_draw_elements_base_vertex GL_ARB_draw_instanced GL_ARB_fragment_program GL_ARB_fragment_program_shadow GL_ARB_fragment_shader GL_ARB_framebuffer_object GL_ARB_framebuffer_sRGB GL_ARB_half_float_pixel GL_ARB_half_float_vertex GL_ARB_imaging GL_ARB_instanced_arrays GL_ARB_multisample GL_ARB_multitexture GL_ARB_occlusion_query GL_ARB_pixel_buffer_object GL_ARB_point_parameters GL_ARB_point_sprite GL_ARB_provoking_vertex GL_ARB_seamless_cube_map GL_ARB_shader_objects GL_ARB_shader_texture_lod GL_ARB_shading_language_100 GL_ARB_shadow GL_ARB_shadow_ambient GL_ARB_sync GL_ARB_texture_border_clamp GL_ARB_texture_compression GL_ARB_texture_compression_rgtc GL_ARB_texture_cube_map GL_ARB_texture_env_add GL_ARB_texture_env_combine GL_ARB_texture_env_crossbar GL_ARB_texture_env_dot3 GL_ARB_texture_float GL_ARB_texture_mirrored_repeat GL_ARB_texture_non_power_of_two GL_ARB_texture_rectangle GL_ARB_texture_rg GL_ARB_transpose_matrix GL_ARB_vertex_array_bgra GL_ARB_vertex_blend GL_ARB_vertex_buffer_object GL_ARB_vertex_program GL_ARB_vertex_shader GL_ARB_window_pos GL_EXT_abgr GL_EXT_bgra GL_EXT_bindable_uniform GL_EXT_blend_color GL_EXT_blend_equation_separate GL_EXT_blend_func_separate GL_EXT_blend_minmax GL_EXT_blend_subtract GL_EXT_clip_volume_hint GL_EXT_debug_label GL_EXT_debug_marker GL_EXT_depth_bounds_test GL_EXT_draw_buffers2 GL_EXT_draw_range_elements GL_EXT_fog_coord GL_EXT_framebuffer_blit GL_EXT_framebuffer_multisample GL_EXT_framebuffer_object GL_EXT_framebuffer_sRGB GL_EXT_geometry_shader4 GL_EXT_gpu_program_parameters GL_EXT_gpu_shader4 GL_EXT_multi_draw_arrays GL_EXT_packed_depth_stencil GL_EXT_packed_float GL_EXT_provoking_vertex GL_EXT_rescale_normal GL_EXT_secondary_color GL_EXT_separate_specular_color GL_EXT_shadow_funcs GL_EXT_stencil_two_side GL_EXT_stencil_wrap GL_EXT_texture_array GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc GL_EXT_texture_env_add GL_EXT_texture_filter_anisotropic GL_EXT_texture_integer GL_EXT_texture_lod_bias GL_EXT_texture_mirror_clamp GL_EXT_texture_rectangle GL_EXT_texture_shared_exponent GL_EXT_texture_sRGB GL_EXT_texture_sRGB_decode GL_EXT_timer_query GL_EXT_transform_feedback GL_EXT_vertex_array_bgra GL_APPLE_aux_depth_stencil GL_APPLE_client_storage GL_APPLE_element_array GL_APPLE_fence GL_APPLE_float_pixels GL_APPLE_flush_buffer_range GL_APPLE_flush_render GL_APPLE_object_purgeable GL_APPLE_packed_pixels GL_APPLE_pixel_buffer GL_APPLE_rgb_422 GL_APPLE_row_bytes GL_APPLE_specular_vector GL_APPLE_texture_range GL_APPLE_transform_hint GL_APPLE_vertex_array_object GL_APPLE_vertex_array_range GL_APPLE_vertex_point_size GL_APPLE_vertex_program_evaluators GL_APPLE_ycbcr_422 GL_ATI_blend_equation_separate GL_ATI_blend_weighted_minmax GL_ATI_separate_stencil GL_ATI_texture_compression_3dc GL_ATI_texture_env_combine3 GL_ATI_texture_float GL_ATI_texture_mirror_once GL_IBM_rasterpos_clip GL_NV_blend_square GL_NV_conditional_render GL_NV_depth_clamp GL_NV_fog_distance GL_NV_light_max_exponent GL_NV_texgen_reflection GL_NV_texture_barrier GL_SGI_color_matrix GL_SGIS_generate_mipmap GL_SGIS_texture_edge_clamp GL_SGIS_texture_lod