This is one of those smart little tricks that is buried in the help menu in Navisworks. You can lock your global options on local machines to prevent accidental changes to settings such as units, viewpoint defaults and file reader settings.
Here is the trick:
Go to Start and then Run.
Enter CMD.exe to launch the DOS Window
The directory will look something like this:
You will need to change the directory by typing CD C:\Program Files\Autodesk\Navisworks Manage 2011 as shown above.
(Note, mine is installed on my D: drive partition, but in most cases this will probably be the user's C: drive)
Hit 'Enter' and then type "optionseditor.exe" -l (That is a space after the quotes and a minus sign in front of the letter "L"). It will take a second of two for the Options Editor to launch. You will then see the following:
Notice the locks! You can lock any settings that you do not want your users to change, thus causing errouneous results in Clash Detective as well as mis-scaled datasets.
The next step is to export these options by selecting the export option on the lower left. Check all the options in the dialog box as shown to the left. You will need to set a project directory location that has a global_options folder in it with the exported options file (*XML) placed in that folder.
Now when you relaunch Navisworks, the options will be locked! This will make the life of VDC and BIM Managers a lot easier!
As a final note, you can find this information , sans screen captures in the help menu by going to this topic: How do I share the Autodesk Navisworks settings on a site and project basis