AutoCAD Civil 3D

[#1]

Anyone know why i can open a drawing from explorer and it takes only about 20 seconds to open, civil3d drawing with surfaces and whatever. But if i open another drawing, then try to close and open the above drawing, instead of 20 seconds it take 10 minutes if it ever does open, most of the time i have to kill the application and go back to opening the drawing from explorer.

any thoughts?

[#2]

One guessing here since no computer, OS or any information was given.  You have run out of memory.

Bill

Notice the info that I include below:

[#3]

Sorry about that, running civil 3d 2012, windows 7 64 bit, 16 gigs or ram.  running with SDI=1 and only 1 session of application running also. 

according to resource manager, not running out of ram.  =(

odd that the exact same drawing would open quickly if it is the first dwg opened, but if you already have opened autocad and do and 'open' command it wil open very slowly. 

Other machines in the same office with same computers and os etc etc do not have the problem. so trying to figure out what setting might have been changed

[#4]

Unplug the Ethernet cable and try again WITHOUT network support.