Not a sigma user, search online indicate negative..so workaround is convert to tiff which double file size or Adobe DNG and use raw processor.
Of course can use native X3F processor with Sigma photo pro (SPP) or japanese software Silkypix ver.8 64 bit which support X3F.
Download a 30 day trial version in the link.
Thanks for reply. SPP is a no no, always crash on Mac. Dun have silkypix. I understand for Quotto series, no issue to read X3F from PS/LR directly with the latest update (i think the update is end of 2017). wondering the M series could be red directly from PS/LR before I committed to buy one.