[Jacques Q.]

Hello.
Thanks for your very quick answer.
I did run Windows in safe mode as advised, tried to create catalog, same result - here is the log (looks pretty much identical to me, except process was much slower) :

Spoiler:

"Générer le catalogue
Sections: Authors, Titles
Catalog_EPUB_MOBI('Bibliothèque calibre'): Generating epub for default in GUI environment, locale: 'French'
connected_device: 'None'
book count: 26674
opts:
author_clip: 100
catalog_title: 'A à Z - Auteurs / Titres'
connected_kindle: False
creator: 'samedi, janvier 15, 2022'
cross_reference_authors: True
description_clip: 380
exclude_genre: '\\[.+\\]|^\\+$'
exclusion_rules: ()
fmt: 'epub'
genre_source_field: 'Étiquettes'
header_note_source_field: ''
merge_comments_rule: '::True'
output_profile: 'default'
prefix_rules: ()
search_text: None
sort_by: None
sort_descriptions_by_author: True
sync: False
thumb_width: '1.00'
use_existing_cover: False
Begin catalog source generation (0:00:00)
Custom fields:
#formats 'Formats' composite
Thumbnails:
DPI = 100; thumbnail dimensions: 100 x 133
Tri des titres (0:01:25)
Tri de la base de données (0:01:25)
Auteurs HTML (0:01:26)
Titres HTML (0:01:42)
Génération de l'OPF (0:02:01)
En-tête NCX (0:02:01)
NCX pour les Auteurs (0:02:01)
NCX pour les Titres (0:02:01)
Sauvegarde du NCX (0:02:02)
Completed catalog source generation (0:02:02)

replacing catalog cover
Conversion options changed from defaults:
cover: 'C:\\Users\\SUPERV~1\\AppData\\Local\\Temp\\calibr e_xf1bc8_v\\thigx7dm.jpg'
remove_fake_margins: False
InputFormatPlugin: HTML Input running
on C:\Users\SUPERV~1\AppData\Local\Temp\calibre_xf1bc 8_v\98mdigwr_epub_mobi_catalog\Catalog.opf
Parsing all content...
Merging user specified metadata...
Detecting structure...
Flattening CSS and remapping font sizes...
Source base font size is 12.00000pt
Cleaning up manifest...
Trimming unused files from manifest...
Creating EPUB Output...
Splitting markup on page breaks and flow limits, if any...
Looking for large trees in content/ByAlphaTitle.html...
Found large tree #0
Found large tree #3
Found large tree #4
Found large tree #5
Found large tree #6
Found large tree #7
Found large tree #8
Found large tree #10
Found large tree #15
Found large tree #20
Found large tree #22
Found large tree #23
Found large tree #24
Split into 50 parts
Looking for large trees in content/ByAlphaAuthor.html...
Found large tree #0
Found large tree #1
Found large tree #2
Found large tree #3
Found large tree #11
Found large tree #12
Found large tree #18
Split into 37 parts
EPUB output written to C:\Users\SUPERV~1\AppData\Local\Temp\calibre_xf1bc 8_v\4t6b_cx8_catalog_out.epub
Catalog creation complete (0:04:54)"