For a particular project, there are 4 clash tests per floor - External Area 1, Internal Area 1, External Area 2, and Internal Area 2. At the beginning, I created one master nwf consisting of NWDs from different trades, then I make 4 copies of that nwf for the different tests. These NWDs were downloaded onto my company's network. The first run of clash test were fine. After the 2nd run of clash tests were done and being reviewed, the NWDs for the Area 2 tests didn't update, but Area 1's did. I checked the properties of the NWDs and it shows the source file as a previous version or from a particular trade's computer. (Note, I run the clash tests for Area 1 and someone else does Area 2) So in short, old files were used to run clash tests for Area 2 but Area 1 was fine even though they are copies of the master nwf file and none of the file names changed. Any idea how this could have happened???