Intel(R) Xeon(R) W3520 @ 2.67 GHz
10 GB RAM
Windows 7 Professional - 64-bit
AutoCAD Civil 3D 2012
I have the exact same issue. Has there been a solution yet? I haven't reinstalled the program since it appears that it doesn't repair the problem. It's definitely annoying and cumbersome.
Try entering this line of code into the command line, and hit enter:
(command "._-color" "ByLayer")
next enter bylayer
Hope this helps!