Vonn, four-times overall World Cup winner and downhill gold medallist at the 2010 Olympics, was racing in the discipline for the first time since early 2016.
After deciding to start her season earlier than usual in an effort to build a decent world ranking and earn a good starting slot at February’s Winter Olympics at Pyeongchang, Vonn finished 34th in the first run, failing to make the cut for the second.
"Not the result I was looking for today but still a positive experience," said Vonn on Twitter. "First GS race in over 600 days...Progress!"
Gut, the overall World Cup winner in 2016 and bronze medallist in the downhill at the Sochi Olympics, retired after around 40 seconds of her first run.
The 26-year-old was racing for the first time since tearing an anterior cruciate ligament in her knee at the world championships in St Moritz in February and had not been expected to race again until November.
"It did me good to race again," Gut told Swiss television. "Of course, I'm still lacking a few kilometres and the rhythm is not yet there."
Germany's Viktoria Rebensburg, gold medallist in the event at the Vancouver Games in 2010, won by 0.14 seconds from France’s Tessa Worley while Italian Manuela Moelgg was third.
(Writing by Brian Homewood in Basel, editing by Pritha Sarkar)
