How to import many .MOV files to Sony Vegas? I have a problem with Sony Vegas. When ever I import too many .MOV files, Sony Vegas Pro 13, doesn't accept them, so they are black in the preview screen. 

However, if I import only 4 or 5 .MOV files to Vegs, it accepts them and I can see the clips in the preview screen. But when I go over that limit of 4 or 5, Sony Vegas doesn't accept the .MOV files, and now all of the clips are black in preview.

How do I make it so that I can import as many .MOV files as I want to SonyVegas.

I have Quicktime installed and also unchecked the option in preferences>video that says something like close media when other apps are open.
This is a known problem. Quicktime for Windows is 32-bit only, and that presents a memory ceiling for the QT handler/decoder. What's worked for me, including in a current project, where I'm working with hundreds of of 5D MkIII files, is to import in batches. Once done, I have no issues loading or working with the project even if many of those are used on the timeline. I should say that often I'm able to import many clips without needing to divide the import step into batches.

As suggested in the linked forum thread, try rolling back to QT 7.6.2 or Quicktime Alternative, and see if that provides a more permanent solution.