Why is my dxf file is empty but visible in Preview?

Hi,
I'm a new LibreCAD user working on a MacBook Pro and have used AutoCAD LT before.
After creating a new drawing I saved it, closed LibreCAD, and then reopened it to find that there was no visible drawing but is still showing as the drawing I created in Preview.
There are no blocks created in the drawing and a search of the forum and Help sections hasn't come up with anything.
Any ideas as to why the drawing is not showing?

Is it really empty? Try Zoom All.
You may also try Select All.

Hi Dellus,
Thank you for your suggestions.
After a few open and closes and using the AutoZoom the drawing then appeared!
Not sure why it didn't work the previous times.