I don't know how it happened but on all my tracks, the compositing mode default is Multiply Mask. Everytime I start Vegas I need to change it to Source Alpha so I can preview my project. I can't figure out how to change the default back to Source Alpha. Can someone help me
This is for the full version of Vegas, so i don't know if Vegas Studio does this or not, but it's worth checking ...
Set the compositing mode to Source (Alpha). Right-mouse-button click on that track's header, from the pop-up menu choose Set Default Track Properties. Make sure Composite mode is checked, though you may want to uncheck everything else. Click OK.
What you probably did was use the Set Default Track Properties function to save some other settings on a track that was set to Multiply(Mask). This got set as the default for all new tracks.