Siril opens file but script claims it does not exist

3:11:54: Welcome to siril v1.2.1
13:11:54: Supported file types: BMP images, PIC images (IRIS), PGM and PPM binary images, RAW images, FITS-CFA images, Films, SER sequences, TIFF images, JPG images, PNG images, HEIF images.
13:11:54: Setting CWD (Current Working Directory) to ‘D:\Lights’
13:11:54: Parallel processing enabled: using 6 logical processors.
13:11:59: Searching scripts in: “C:\Program Files\Siril\scripts”…
13:11:59: Loading script: AstroBBQ_StackLightsDarksFlatsBiasesHubbleRelaxed
13:11:59: Loading script: AstroBBQ_StackLightsDarksFlatsHubbleRelaxed
13:11:59: Loading script: AstroBBQ_StackLightsDarksHubbleRelaxed
13:11:59: Loading script: AstroBBQ_StackLightsHubbleRelaxed
13:11:59: Loading script: Mono_Preprocessing
13:11:59: Loading script: OSC_Extract_Ha
13:11:59: Loading script: OSC_Extract_HaOIII
13:11:59: Loading script: OSC_Preprocessing
13:11:59: Loading script: OSC_Preprocessing_withbackgroundextraction
13:11:59: Loading script: OSC_Preprocessing_WithDrizzle
13:11:59: Loading script: OSC_Preprocessing_WithoutDBF
13:11:59: Loading script: OSC_Startrail
13:11:59: Loading script: RGB_Composition
13:11:59: Loading registration method: 1-2-3 Stars Registration (deep-sky)
13:11:59: Loading registration method: Global Star Alignment (deep-sky)
13:11:59: Loading registration method: Two-Pass Global Star Alignment (deep-sky)
13:11:59: Loading registration method: Image Pattern Alignment (planetary - full disk)
13:11:59: Loading registration method: KOMBAT (planetary surfaces or full disk)
13:11:59: Loading registration method: Comet/Asteroid Registration
13:11:59: Loading registration method: Apply Existing Registration
13:11:59: Default FITS extension is set to .fit
13:12:12: Setting CWD (Current Working Directory) to ‘D:\Lights’
13:12:21: Starting script C:\Program Files\Siril\scripts\OSC_Preprocessing_WithoutDBF.ssf
13:12:21: ############################################
13:12:21: # Script for Siril 1.0
13:12:21: # August 2020
13:12:21: # (C) Cyril Richard / Colmic
13:12:21: # OSC_Preprocessing_WithoutDBF v1.0
13:12:21: #
13:12:21: ########### PREPROCESSING SCRIPT ###########
13:12:21: # Script for color camera preprocessing
13:12:21: # needs 1 set of RAW images in the working
13:12:21: # directory, within 1 directory:
13:12:21: # lights
13:12:21: #
13:12:21: ############################################
13:12:21: Running command: requires
13:12:21: #preprocess lights
13:12:21: Running command: cd
13:12:21: ‘lights’ No such file or directory
13:12:21: Error in line 18 (‘cd’): generic error.
13:12:21: Exiting batch processing.
13:12:21: Setting CWD (Current Working Directory) to ‘D:\Lights’
13:12:21: Script execution failed.
[/quote]

This is the common error.

Please, have a look here : Scripts — Siril 1.2.0 documentation

I have followed your advice but am still receiving the same error :-
18:34:11: Welcome to siril v1.2.1
18:34:11: Supported file types: BMP images, PIC images (IRIS), PGM and PPM binary images, RAW images, FITS-CFA images, Films, SER sequences, TIFF images, JPG images, PNG images, HEIF images.
18:34:11: Setting CWD (Current Working Directory) to ‘D:\Users\Siril\lights’
18:34:11: Parallel processing enabled: using 6 logical processors.
18:34:16: Searching scripts in: “C:\Program Files\Siril\scripts”…
18:34:16: Loading script: Mono_Preprocessing
18:34:16: Loading script: OSC_Extract_Ha
18:34:16: Loading script: OSC_Extract_HaOIII
18:34:16: Loading script: OSC_Preprocessing
18:34:16: Loading script: OSC_Preprocessing_withbackgroundextraction
18:34:16: Loading script: OSC_Preprocessing_WithDrizzle
18:34:16: Loading script: OSC_Preprocessing_WithoutDBF
18:34:16: Loading script: OSC_Startrail
18:34:16: Loading script: RGB_Composition
18:34:16: Loading registration method: 1-2-3 Stars Registration (deep-sky)
18:34:16: Loading registration method: Global Star Alignment (deep-sky)
18:34:16: Loading registration method: Two-Pass Global Star Alignment (deep-sky)
18:34:16: Loading registration method: Image Pattern Alignment (planetary - full disk)
18:34:16: Loading registration method: KOMBAT (planetary surfaces or full disk)
18:34:16: Loading registration method: Comet/Asteroid Registration
18:34:16: Loading registration method: Apply Existing Registration
18:34:16: Default FITS extension is set to .fit
18:37:28: Setting CWD (Current Working Directory) to ‘D:\Users\Siril\lights’
18:38:17: Starting script C:\Program Files\Siril\scripts\OSC_Preprocessing_WithoutDBF.ssf
18:38:17: ############################################
18:38:17: # Script for Siril 1.0
18:38:17: # August 2020
18:38:17: # (C) Cyril Richard / Colmic
18:38:17: # OSC_Preprocessing_WithoutDBF v1.0
18:38:17: #
18:38:17: ########### PREPROCESSING SCRIPT ###########
18:38:17: # Script for color camera preprocessing
18:38:17: # needs 1 set of RAW images in the working
18:38:17: # directory, within 1 directory:
18:38:17: # lights
18:38:17: #
18:38:17: ############################################
18:38:17: Running command: requires
18:38:17: #preprocess lights
18:38:17: Running command: cd
18:38:17: ‘lights’ No such file or directory
18:38:17: Error in line 18 (‘cd’): generic error.
18:38:17: Exiting batch processing.
18:38:17: Setting CWD (Current Working Directory) to ‘D:\Users\Siril\lights’
18:38:17: Script execution failed.

Because your working directory, as written in the title bar, is not good

I have relocated the “lights” folder & am still receiving the same error :-
20:13:38: Welcome to siril v1.2.1
20:13:38: Supported file types: BMP images, PIC images (IRIS), PGM and PPM binary images, RAW images, FITS-CFA images, Films, SER sequences, TIFF images, JPG images, PNG images, HEIF images.
20:13:38: Setting CWD (Current Working Directory) to ‘D:\lights’
20:13:38: Parallel processing enabled: using 6 logical processors.
20:13:43: Searching scripts in: “C:\Program Files\Siril\scripts”…
20:13:43: Loading script: Mono_Preprocessing
20:13:43: Loading script: OSC_Extract_Ha
20:13:43: Loading script: OSC_Extract_HaOIII
20:13:43: Loading script: OSC_Preprocessing
20:13:43: Loading script: OSC_Preprocessing_withbackgroundextraction
20:13:43: Loading script: OSC_Preprocessing_WithDrizzle
20:13:43: Loading script: OSC_Preprocessing_WithoutDBF
20:13:43: Loading script: OSC_Startrail
20:13:43: Loading script: RGB_Composition
20:13:43: Loading registration method: 1-2-3 Stars Registration (deep-sky)
20:13:43: Loading registration method: Global Star Alignment (deep-sky)
20:13:43: Loading registration method: Two-Pass Global Star Alignment (deep-sky)
20:13:43: Loading registration method: Image Pattern Alignment (planetary - full disk)
20:13:43: Loading registration method: KOMBAT (planetary surfaces or full disk)
20:13:43: Loading registration method: Comet/Asteroid Registration
20:13:43: Loading registration method: Apply Existing Registration
20:13:43: Default FITS extension is set to .fit
20:13:53: Setting CWD (Current Working Directory) to ‘D:\lights’
20:14:03: Starting script C:\Program Files\Siril\scripts\OSC_Preprocessing_WithoutDBF.ssf
20:14:03: ############################################
20:14:03: # Script for Siril 1.0
20:14:03: # August 2020
20:14:03: # (C) Cyril Richard / Colmic
20:14:03: # OSC_Preprocessing_WithoutDBF v1.0
20:14:03: #
20:14:03: ########### PREPROCESSING SCRIPT ###########
20:14:03: # Script for color camera preprocessing
20:14:03: # needs 1 set of RAW images in the working
20:14:03: # directory, within 1 directory:
20:14:03: # lights
20:14:03: #
20:14:03: ############################################
20:14:03: Running command: requires
20:14:03: #preprocess lights
20:14:03: Running command: cd
20:14:03: ‘lights’ No such file or directory
20:14:03: Error in line 18 (‘cd’): generic error.
20:14:03: Exiting batch processing.

please send a screenshot of the whole app. But I see at the beginning of the script:
20:13:53: Setting CWD (Current Working Directory) to ‘D:\lights’
That means your cwd is in Lights, which is wrong.

I can’t explain better than this picture.