@Tim Edwards I am trying to open a GDS file (https://redmine.libresilicon.com/projects/danube-river/repository/47/revisions/master/entry/tapeout/gf180.gds ) that is produced by gdsfactory in magic, it opens (UNNAMED), so I open the cellmanager, and when I try to expand the tree I get this error:

No idea what's going on without looking at it in detail.

(That's one of the reasons why I prefer .mag over .gds , I am not sure whether the file is incorrectly generated by gdsfactory or incorrectly loaded by magic. I could take a look with a texteditor into a .mag file and decide whether the file is OK or not. But I can't open the gds file with a hexeditor and figure that out. And that's my 3rd time that I have interoperability issues with GDS files.)

Well, the cell manager is just a really simple Tcl script and is not necessarily robust to anything unusual it encounters.

That issue isn't urgent for me at the moment.