Please go to
Edit menu and select
Current Drawing Preferences ....
In the
Paper tab set a valid size for
Custom paper size or select an other preset paper size from the list.
The paper size for your drawing is much too small. I'll check if this is a LibreCAD issue, if we have to initialize the values for new drawings.
I can confirm, that the PDF is empty, with this paper size. With a print scale factor of 1:200000 the print preview is OK, but PDF and printing doesn't work.
With a valid paper size of A4 and a print scale factor of 1"=16" the PDF export works well for me.
Armin
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