Sue
You may be experiencing the outworking of a known bug that is specific to 5d Mkiii. Typically, it results in the previews taking a long while to appear and actual import to take even longer. In my case the first preview may take 20 seconds or more to show. The first file to actually appear in Lightroom might take another minute, and import of all files more than 5 times longer than normal.
Note that witching to DNG might help, it did so only marginaly in my case.
QE are aware of the issue and working to find a fix.
