6D file numbering inconsistent

Hi Forum,

Need some advice.  I have just got the Canon 6D an a have uploaded my files using the adobe downloader.

Up to today the file number has been iMG_xxxx CR2, but since this afternoon, it has been _MGxxxx CR2.  Any thought about what has happened here.  I am shooting in RAW +Jpg.

This could be a pain at some later stage as I would like my Tiff files to have the same numbers as my RAW files for future references.

Any ideas on more efficient ways of file numbering would be greatly appreciated.

Cheers,

Ben