The following has happened more than once and I consider it to be an intermittent but repeatable possible bug in SolidWorks 2004, SP2.1:
I typically have the System Option for Performance set ON for Loading Components Lightweight. From time to time, when I've already successfully opened one assembly in lightweight state and have NOT manually turned the system option OFF, a subsequent assembly opening takes an exceedingly long time and presents itself completely RESOLVED.
If I then look at the Systems Options for Performance, the "Automatically Load Components Lightweight" setting is mysteriously turned OFF.
It seems that certain assemblies are having the effect of toggling the setting. Perhaps it has something to do with files that have not yet been converted to 2004 format, but I don't recall this sort of situation with version transitions in the past.
Have others seen this erratic behavior? I, for one, am frustrated by the undesired system option toggle...
Per O. Hoel