Glyph file inexplicably too big

Hi there. I think it’s not normal that my glyphs file is about 8 mb with just 141 glyphs in it and no images at all. I did run the script to delete all of them but nothing changed. Any suggestion? I also noticed that when I delete all the stylistic set the size of file comes back to a normal value

Many backup layers maybe?

Every glyphs has like from 2 to 10 layers. Is this the reason why?

And also when I tried to copy a bunch of glyphs, a pop up shows up saying :
Data can not be written because an error occurred in the data destination. I cannot understand what it means

What version of Glyphs do you have?

A file with only so few glyphs should not be so big. It seems that your outlines are a bit to complex.

The copy paste problem should be fixed in the latest cutting edge version.

Not That complex. Can I send you the file? I have Version 2.5.2 (1181)

You have used the LayerWhale plugin. It saves a lot data inside the .glyphs file. I need to have a look at it.