Problem with clips going grey / disappearing

Hi all!

I'm super new to Resolve, just started toying around with it this month.

Yesterday I was doing a first pass at color correcting four clips. They're h.264 .mp4 files recorded on a DJI Phantom. I'm using Resolve 12 Beta on a macbook running OS 10.9. Everything was going along just fine yesterday. I saved my project and shut down the computer.

This morning I boot up Resolve and am greeted by this:
Three of the four clips are now greyed out. The one remaining is only sometimes playable (over several restarts of software and computer).

The clips have not changed name or location on my drive, and when I right click the blank clips and "reveal in finder," it sends me to the folder all four are still in. However, when I click "reveal in media storage," I get this this error:

"Unable to find media
Davinci resolve cannot find this media: [path to file]

Please check the path, or change parent folder if it has moved."

...And navigating through the media storage window I still only see blank clips. I tried "relink selected media" but nothing happened when I directed it to the folder.

Why would this be? Did my laptop forget a codec over night? Is Resolve just too much for my hardware to handle, and I somehow got lucky yesterday?

Thanks!

H.264 and MP4 files are not optimal for post in my opinion, because many (but not all) of them are Long-GOP formats that have a lot of overhead.

I think you're better off converting the files to a more-compatible format like QuickTime or DNxHD (or DNxHR in the case of 4K). DPX can also work provided you have lots of horsepower.

If the files are balky, re-import them into the Media page, then use Force Conform to the clips again to re-establish the links. You might also check Preferences -> Media Storage and make sure the drive has been added to the available pool.