I have noticed that while working for an extended period of time with templates, going back and forth between templates, or switching many times between items in a single template, I begin getting a "Memory Low" message but can still continue to work. At some later point ChemDraw does finally lock up.
ChemDraw never closes a template file once you select from it, and it will quickly run out of memory if you try to use many template files in a small partition. There are two suggestions:
1. You can cause ChemDraw to close a template file by selecting it from the Windows menu and closing the window. 2. As a rule of thumb, a template takes memory equal to four times the file size. The largest file, Hexoses, is about 60K, and it uses 240K of RAM when open. If you're going to use every one of the templates we ship with ChemDraw, increase the application memory by an extra 1200K. To increase the allocated memory to ChemDraw, make sure ChemDraw is not open, and then click once on the ChemDraw application icon. Choose Get Info from the File menu and changed the Preferred size in the Info dialog box. Close this dialog box to commit the change.