I was having the same problem when trying to import to a project based on my Macintosh HD not an external HD, BUT… I realised I simply had to change to “Private” rather than “External” in Avid’s ‘Select Project’ window 🙂
Download and install these “ProApps” QuickTime codecs to get Quicktime to open the files normally without converting and also to resolve the Quickview (Spacebar Preview) issue.
It’s free from Apple. Why they didn’t just leave them there for Mavericks, I do not know.
The codec adds back support for these formats:
•Apple Intermediate Codec
•Apple ProRes
•AVC-Intra
•DVCPRO HD
•HDV
•XDCAM HD / EX / HD422
•MPEG IMX
•Uncompressed 4:2:2
•XAVC