Im having the same problem
Found this in Plex Media Scanner.log
Dec 20, 2019 18:21:57.778 [0x14f2fa5a6740] ERROR - SQLITE3:(nil), 1, table media_items has no column named color_trc in "insert into media_items (library_section_id,section_location_id,metadata_item_id,type_id,width,height,size,duration,bitrate,container,video_codec,audio_codec
Dec 20, 2019 18:21:57.779 [0x14f2fa5a6740] ERROR - Exception inside transaction (inside=1) (../Library/MetadataItem.cpp:3572): sqlite3_statement_backend::prepare: table media_items has no column named color_trc for SQL: insert into media_items (library_section_id,section_location_id,metadata_item_id,type_id,width,height,size,duration,bitrate,container,video_codec,audio_codec,display_aspect_ratio,frames_per_second,audio_channels,interlaced,source,hints,display_offset,settings,created_at,updated_at,optimized_for_streaming,deleted_at,media_analysis_version,sample_aspect_ratio,proxy_type,extra_data,channel_id,begins_at,ends_at,color_trc) values (:media_items_library_section_id,:media_items_section_location_id,:media_items_metadata_item_id,:media_items_type_id,:media_items_width,:media_items_height,:media_items_size,:media_items_duration,:media_items_bitrate,:media_items_container,:media_items_video_codec,:media_items_audio_codec,:media_items_display_aspect_ratio,:media_items_frames_per_second,:media_items_audio_channels,:media_items_interlaced,:media_items_source,:media_items_hints,:media_items_display_offset,:media_items_settings,:media_items_created_at,:media_items_updated_at,:media_items_optimized_for_streaming,:media_items_deleted_at,:media_items_media_analysis_version,:media_items_sample_aspect_ratio,:media_items_proxy_type,:media_items_extra_data,:media_items_channel_id,:media_items_begins_at,:media_items_ends_at,:media_items_color_trc)
Dec 20, 2019 18:21:57.779 [0x14f2fa5a6740] ERROR - Exception assimilating media item in chronohd-ronja720: sqlite3_statement_backend::prepare: table media_items has no column named color_trc for SQL: insert into media_items (library_section_id,section_location_id,metadata_item_id,type_id,width,height,size,duration,bitrate,container,video_codec,audio_codec,display_aspect_ratio,frames_per_second,audio_channels,interlaced,source,hints,display_offset,settings,created_at,updated_at,optimized_for_streaming,deleted_at,media_analysis_version,sample_aspect_ratio,proxy_type,extra_data,channel_id,begins_at,ends_at,color_trc) values (:media_items_library_section_id,:media_items_section_location_id,:media_items_metadata_item_id,:media_items_type_id,:media_items_width,:media_items_height,:media_items_size,:media_items_duration,:media_items_bitrate,:media_items_container,:media_items_video_codec,:media_items_audio_codec,:media_items_display_aspect_ratio,:media_items_frames_per_second,:media_items_audio_channels,:media_items_interlaced,:media_items_source,:media_items_hints,:media_items_display_offset,:media_items_settings,:media_items_created_at,:media_items_updated_at,:media_items_optimized_for_streaming,:media_items_deleted_at,:media_items_media_analysis_version,:media_items_sample_aspect_ratio,:media_items_proxy_type,:media_items_extra_data,:media_items_channel_id,:media_items_begins_at,:media_items_ends_at,:media_items_color_trc)
Googled it and found:
https://forums.plex.tv/t/1-18-2-2058-and-table-media-items-has-no-column-named-color-trc-error/497167
Seems it's a plex problem and reverting to 1.17 will fix it, gonna try it later.
edit:
reverted to 1.17.0.1841-1-01 and now everything works again
