Can't find source clips for synchronized clips

You may have 2 separate problems here: First, finding the source clips and second exporting/importing into Davinci.

Let's deal with the first one first to see if we can find your original video clips. Any clip can be found by FCPX (unless the original media was destroyed). To find your original clip, follow these steps:

1. Select your synchronized clip in the Browser.
2. Under the Clip menu go to Open Clip command
3. Your synchronized clip will open revealing the original clips that were joined.
4. Right-click on the Video clip and choose Reveal in Browser. This will highlight the Original Clip.
5. If you're looking for where the Original Clip is stored on your HD, Right-click on this Highlighted clip and select Reveal in Finder.

Let us know how that goes! :)

Ok, so good, it's not the first problem then. It sounds like the export/import is definitely the issue, and that Davinci can't see the clips. Some questions for you:

1. What version of Mac OS?
2. What version of FCPX?
3. What version of Davinci Resolve?
4. Do you have any compound clips on your timeline? A screenshot of your timeline would be helpful.
5. Does your XML reference a managed library? If so, according to Steve at Ripple Training, "If you imported an XML file that references a managed Library, you’ll need to navigate to the Library on your hard drive and select it. If you imported an XML file that references media in an external folder, you’ll want to navigate to that folder and select it."

It appears you are not alone.

http://forum.blackmagicdesign.com/viewtopic.php?f=3&t=24235

There's probably some setting either in FCPX or Resolve that is off, or it could be compound clips? But tell us how things are going...