Posted by dellus on May 30, 2021; 8:40pm
URL: https://forum.librecad.org/Print-Preview-Shows-Lines-Thicker-tp5720706p5720707.html

Are really all lines drawn with 0.00 mm? Have you drawn it yourself? Best you provide the file here.
You can change line properties with Modify - Properties (single entity) or -Attributes (multiple entities).
Might also be an issue of layer properties.