Aha! I can't believe I was so dumb not to notice that I have my external drive, where my photos are, was turned off!     Sorry to bother you.  Thanks so much for the answer! ... View more

Yes of course. ... View more

Sulco, same here.  So frustrating. ... View more

"THIS MORNING I got a good tech on the phone and thru a screen share he fixed the issue" Are you able to share the fix? ... View more

I'll paste my System Info for you. But it's not a systems issue.  Use some logic here, by taking the time to read the posts in this forum and other forums like the one I linked to in another thread here, you should quickly understand that it started with 7.3, and affects people who have an attached external drive. Period.  Exiting and restarting LR after the Not Responding occurs, tells you it's not a systems issue.  It's very simple. Also, could you please let us know the size of the Lightroom catalog you are using now? Have you tried creating a new Lightroom catalog with some sample images and check the performance? This makes no difference.  It's the same size after I exit and restart LR.  But here's the size for you: Lightroom Catalog-2.lrcat is 401MB. No I have not tried to build a new LR catalog, and I'm not going to build one and waste a day leaving LR sitting around unused until it stops responding as it could take up to a day.  On what step, Lightroom goes to "Not Responding" error message? Like, when you are editing an image in develop module Or going through images in library module? This is written up all over the forums already. LR is open and not used it a while.  Then I click on the icon in the doc and once in LR anything I click, Develop or Library, hangs the app. Could you please share your system info with us? Go to Lightroom > help menu > system info and provide the dialogue information Here's my info: Lightroom Classic version: 7.4 [ 1176617 ] License: Creative Cloud Language setting: en-US Operating system: Mac OS 10 Version: 10.13.6 [17G65] Application architecture: x64 Logical processor count: 8 Processor speed: 4.0 GHz Built-in memory: 32,768.0 MB Real memory available to Lightroom: 32,768.0 MB Real memory used by Lightroom: 2,369.6 MB (7.2%) Virtual memory used by Lightroom: 4,882.9 MB Memory cache size: 33.4MB Internal Camera Raw revision: 976 Maximum thread count used by Camera Raw: 5 Camera Raw SIMD optimization: SSE2,AVX,AVX2 Camera Raw virtual memory: 294MB / 16383MB (1%) Camera Raw real memory: 300MB / 32768MB (0%) Displays: 1) 5120x2880 Graphics Processor Info: Metal: AMD Radeon R9 M395 Application folder: /Applications/Adobe Lightroom Classic CC Library Path: /Users/mark/Dropbox/Lightroom/Lightroom Catalog-2.lrcat Settings Folder: /Users/mark/Library/Application Support/Adobe/Lightroom Installed Plugins: 1) AdobeStock 2) Aperture/iPhoto Importer Plug-in 3) Canon Tether Plugin 4) Flickr 5) HDR Efex Pro 2 6) Luminar 7) Luminar 2018 8) Nikon Tether Plugin Config.lua flags: None AudioDeviceIOBlockSize: 512 AudioDeviceName: Built-in Output AudioDeviceNumberOfChannels: 2 AudioDeviceSampleRate: 44100 Build: 10.0x7 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 R9 M395 OpenGL Engine GL_SHADING_LANGUAGE_VERSION: 1.20 GL_STENCIL_BITS: 8 GL_VENDOR: ATI Technologies Inc. GL_VERSION: 2.1 ATI-1.68.20 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 ... 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I've been through this and so have others. Not going to do it again.  Here's what you need to know:  When LR is stuck not responding, if you quit it and then restart it, it works great.  So nothing has changed except I've quit and restarted LR. The rest of my computer is the same. There are many threads on the web that discuss this. Here's one that will explain it to you without me rewriting the pertinent facts.  Note that this all started for people after they installed 7.3, and if they have an external drive attached. https://feedback.photoshop.com/photoshop_family/topics/lightroom-classic-cc-not-responding-constantly ... View more

"Most of the times "Not Responding" means there's not sufficient system resource." Very powerful iMac, 32GB of memory, no other applications working.  It's an Adobe problem, period. ... View more

"I'm at the point that I'm ready to find another photo processing program. It's an insult to have to pay for this abuse. get me a diagnostic tool and I'll run it to get Adobe some additional data as I encounter this problem with every LR Classic CC use." I own Luminar 2018, and later this year they are adding an image management system to it too compete with LR.  It's an awesome app already, and I'm excited to see how it will compete!  (And they actually have a support staff that replies to you and seems to care) ... View more

"Why aren't Adobe addressing what is clearly a very common problem?" They very often don't.  Not good business practice, but that's Adobe. ... View more

I've got this fixed up. Whew, took a long time to figure out. It's not the fault of Adobe, but is a MacOS issue. First, I had to Rebuild Launch Services.  I used the function on CleanMyMac 3 to do this, but a search will show you how to do this easily without it. Then I had some other issues, and you can see the problem in my thread at Apple.  You may or may not have this issue after the step above. ... View more

I appreciate the information.  But I am not going to attempt all that.  The problem is that Lightroom and Photoshop are just to buggy and unpredictable. I'd be afraid that something with my catalog or preferences would get screwed up in the process.  And besides, usually when I do something like this uninstall/reinstall approach it simply doesn't help anyway.  And it could come right back.  In fact, I had this same error a couple weeks ago, at which time I got it working again by uninstalling/reinstalling Photoshop and using CleanMyMac 3 to Rebuild Launch Services (read this by someone who tried everything, including instructions similar to what you suggested). As it is now, I can get LR to hand off an image to PS if PS is already open at the time.  So I just have to remember to bring it up first.  All my other "Edit In..." handoffs to other apps are working fine. But, thank you. ... View more

I've got the exact same issue, for the last month or so, and I have TONS of disk space and 32 GB of data.  After starting up LRCC, ti works for as long as I am active in it, but once it sits idle for a few hours, then it goes into this barely/un responsive state. I've looked around the web for an answer.  There are many people having this issue and there seems to be no solution.  All I can do it quite LR and then restart it--then it's good to go for a while. ... View more

Thank you very much!  Great explanation. ... View more

I was having the same problem as the originator of this thread. Thank you.  But I know have another issue I think might be related, so I'm hoping you might know the answer. After the change you suggested in your answer, and then after executing the Edit in Photoshop, once in PS when I bring up the Camera Raw filter it only shows As Shot, Auto and Custom White Balance pull down choices.  Yet, looking back in Lightroom at the image, it shows all the other usual choices as well, such as Cloudy, Shady, etc. This discrepancy makes me wonder if there's still some mismatch between Lightroom and Photoshop. (My versions are up to date CC 2015 on Yosemite.) ... View more