Hi,again.
To sum it up:
When working with AVCHD you have two options.
1. You can import directly from the SD Card — go to import from camera for that.
2. You can copy the full — with all folders, exactly everything that is on the card — contents of the SD card to a folder on your hard drive an archive it that way. If you want to import an archived SD card later on you can go to import from camera and then go for the open archive button, then point to the folder where you keep the back up of that specific card.
It is not possible to import .mts files on their own.
AVCHD on Final Cut needs camera data that is included in the other folders of the SD card.
That's why it's called "Import from camera", even if you only insert the card directly.
If you only backed up the .mts files and that's all you have you will have to convert them outside of Final Cut beforehand. I recommend to make the best of the situation and just download the free tool called "Handbrake".
With Handbrake simply convert the .mts files to mp4 with the same bitrate. You won't lose that much quality. It's really no big deal.
So, if your camera records with AVCHD 17 Mbit for example, convert to mp4 with 17 Mbits. And then import to Final Cut.
In the future be more careful of what you do: read the documentation before you delete something and try to keep a full backup of your cards. I always have a card backup in the project folder, because AVCHD doesn't need that much space anyway.
Hope that helps.