Polyline won't complete

I am having trouble completing polylines– which only applies when I am working on this specific file.

I can click points and draw lines- However, as I come to complete the line by clicking enter or closing the curve, an error icon appears next to my mouse and the line disappears.

Thanks for your help

RoofPiece.3dm (19.2 MB)

I cannot reproduce that error here (but I’m on Windows…).
What does the error icon look like?

Also - and likely the cause of your troubles - you are working in a document with units set to mm and your objects are about 180 km away from the origin. Is the problem still there if you move all to the origin?

I have moved the geometry to (0,0,0) and had a go at changing the units, but unfortunately the error still occurs.

The error icon is as follows- which appears as I finish the polyline before disappearing…

Shouldnt you chceked this box? Just my guess.

It worked! very simple in the end. Thank you so much