Physical Properties do not update in a part file.
Solution One of the common reasons for this is that Maintain Relationships is turned off in the file. To check, go to Tools tab and click the Update Active Level pulldown, check the Automatic Update icon: it should be selected. The icon should have a light blue background. If not, click on it to turn it on. That should allow the Physical Properties to work correctly again. It is recommended that Automatic Update is kept on at all times. This option is stored with the file and is NOT a user preference.
Notes and References
Hardware/Software Configuration Platform: INTEL
OS Version: 764SP1