I normally use Mechanical and Inventor, so Im not all that familiar with Electrical.

Ive been using the same ctb pen settings file for probably 15 years.and I triple checked that all colors were set to plot as black.

If I click on the color, it takes me to a window where I can chooseset the color.

There is a tab for Index Color, a tab for True Color and a tab for Color Books.

I dont see anywhere to set it to use the index color and not the true color.

Those are index colors and should plot black according you what you have said.

With the only difference being that you went to 2015 I dont know what else to suggest, but others will no doubt be along with some suggestions.

Im not sure if this is new to 2015 but its something Ive never run into in 20 years of doing this.

I was trying to access the plot style editor but every time I did.it just gave me a confusing error message.

All the index colors in the plot style were set to plot as black.

As far as I can tell, all the settings are the same but it plotted as expected from the new file.

Another user resolved the problem by changing LAYOUTREGENCTL variable.

The problem was caused by the Viewport or viewports configuration.

What you can do is use the command Mview, then select shadeplot, then select Wireframe or Hidden, and then select the viewports in your drawing that are being plotted in color, and finish with Enter.

If I switch to a different plot style file, it works just fine.

All of the variables are set to black and match, from what I can tell, the other plot style file which DOES work.

Ive made sure theyre all index colors, and have additionally played with stb vs ctb files.

Plot Styles Don'T Work Autocad For Mac