P: When trying to add files to Collections I get this error: ?:0: attempt to compare two nil values

@John_R_Ellis  Yes!!  I changed over to Sort by Capture time in View within the said Collection and voilà! It allowed me to move images into the Collection from other Collections and my Folders in the Catalog.  Thanks for the tip.  Support did tell me that this is a known problem and there would be a fix "soon".

Same problem. Details for my specific situation are at the following thread:

https://community.adobe.com/t5/lightroom-classic/on-add-to-collection-0-attempt-to-compare-two-nil-values/m-p/11536528?page=1#M208659

And my System Info is:

Lightroom Classic version: 10.0 [ 202010011851-ef6045e0 ]
License: Creative Cloud
Language setting: en
Operating system: Mac OS 10
Version: 10.15.7 [19H2]
Application architecture: x64
Logical processor count: 16
Processor speed: 3.6 GHz
SqLite Version: 3.30.1
Built-in memory: 32,768.0 MB
Real memory available to Lightroom: 32,768.0 MB
Real memory used by Lightroom: 4,259.5 MB (12.9%)
Virtual memory used by Lightroom: 24,899.2 MB
Memory cache size: 2,354.3MB
Internal Camera Raw version: 13.0 [ 610 ]
Maximum thread count used by Camera Raw: 5
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 215MB / 16383MB (1%)
Camera Raw real memory: 224MB / 32768MB (0%)
Displays: 1) 5120x2880, 2) 1920x1200

Graphics Processor Info: 
Metal: AMD Radeon Pro 580X

Application folder: /Applications/Adobe Lightroom Classic
Library Path: /Users/berdine/Pictures/Lightroom/DPB Primary LR Catalog-v10.lrcat
Settings Folder: /Users/berdine/Library/Application Support/Adobe/Lightroom

Installed Plugins: 
1) AdobeStock

Config.lua flags: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: $$$/dvaaudiodevice/SystemDefaultAndEffectiveDeviceName=System Default (Built-in Output)#{comment}DVAAU-4201250: Open the audio hardware preferences page.
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 44100
Build: LR5x42
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-3.10.18
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 

Hello,

I regularly use collections in my workflow but I started having issues while trying to add photos to a few of my collections today. When I try to add photos to certain collections I receive the error message  (?:0: attempt to compare two nil values) I have restarted LR Classic but the issue still persists. I'm using Mac OSX 10.15.6 and LR Classic 10.

Thanks in advance for any help.

- Mike

"I changed the sort order in the destination to 'Capture Time' and suddenly it worked. When switching back to 'Custom order' the error reappears."

LR 10 has a new implementation of Custom Order (that fixed old bugs). Unfortunately, that new implementation also has bugs that are causing the problems in this thread. LR sometimes stores "nil" for the custom-order position of an image within a collection, which then causes the error messages reported here.

See the other bug report for gory technical details:

https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-classic-limit-of-52-reorderings-in-customordered-collections-and-folders/5f5f45b94b561a3d425c094f?commentId=5f91f13549d3ca75248dcdf2

Very strange: I changed the sort order in the destination to 'Capture Time' and suddenly it worked. When switching back to 'Custom order' the error reappears.

Same here, sort order is 'User defined':

Lightroom Classic-Version: 10.0 [ 202010011851-ef6045e0 ]
Lizenz: Creative Cloud
Spracheinstellung: de-DE
Betriebssystem: Mac OS 10
Version: 10.15.7 [19H2]
Anwendungsarchitektur: x64
Anzahl logischer Prozessoren: 12
Prozessorgeschwindigkeit: 3,2 GHz
SQLite-Version: 3.30.1
Integrierter Speicher: 32.768,0 MB
Für Lightroom verfügbarer phys. Speicher: 32.768,0 MB
Von Lightroom verwendeter phys. Speicher: 3.467,1 MB (10,5%)
Von Lightroom verwendeter virtueller Speicher: 16.225,8 MB
Cache-Speichergröße: 898,9MB
Interne Camera Raw-Version: 13.0 [ 610 ]
Maximale Anzahl Threads, die Camera Raw verwendet: 5
Camera Raw SIMD-Optimierung: SSE2,AVX,AVX2
Virtueller Speicher in Camera Raw: 890MB / 16383MB (5%)
Physischer Speicher in Camera Raw: 997MB / 32768MB (3%)
Monitore/Anzeigegeräte: 1) 5120x2880

Informationen zum Grafikprozessor: 
Metal: AMD Radeon RX Vega 64

Anwendungsordner: /Applications/Adobe Lightroom Classic
Bibliothekspfad: /Users/asadmin/Pictures/Lightroom/Fotoarchiv komplet/Fotoarchiv komplet-v10.lrcat
Einstellungen-Ordner: /Users/asadmin/Library/Application Support/Adobe/Lightroom

Installierte Zusatzmodule: 
1) AdobeStock
2) Aperture/iPhoto-Import-Zusatzmodul
3) DENOISE projects 3 professional
4) Excire Search
5) Exportiere nach PanoramaStudio 2
6) Facebook
7) Find Duplicates 2
😎 Flickr
9) Focus Point Viewer
10) Helicon Focus Export
11) Mirage Drucken
12) SHARPEN projects 3 professional
13) Teekesselchen

Config.lua-Flags: None

AudioDeviceIOBlockSize: 512
AudioDeviceName: $$$/dvaaudiodevice/SystemDefaultAndEffectiveDeviceName=System Default (Externe Kopfhörer)#{comment}DVAAU-4201250: Open the audio hardware preferences page.
AudioDeviceNumberOfChannels: 2
AudioDeviceSampleRate: 48000
Build: LR5x42
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 RX Vega 64 OpenGL Engine
GL_SHADING_LANGUAGE_VERSION: 1.20
GL_STENCIL_BITS: 8
GL_VENDOR: ATI Technologies Inc.
GL_VERSION: 2.1 ATI-3.10.18
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 

This happened to me when trying to move some images into a specific folder that's linked to an online gallery (format.com). I made a new folder on format, transferred the existing images to it, and now I can add the new images as well. I have dozens of other folders on the same server, for some reason one got corrupted. Hope that helps for others.

Obviously my first post.  Thanks

You only need to do the SAME post once.

Why conversations get merged: https://feedback.photoshop.com/conversations/lightroom-classic/lightroom-auto-import-to-folders-organized-by-date/5f5f44f14b561a3d422ab0ba?commentId=5f5f48984b561a3d422bdf45