As Uber continues to stumble through 2017, the controversial ride-sharing company has lost another key executive.
The latest high-profile departure is Sherif Marakby, Uber's vice president of global vehicle programmes and one of the main players in the company's development of self-driving cars.
Marakby only joined Uber in April 2016, having been poached from Ford after a 25-year career at the car maker. Marakby left Ford after serving as director of global electronics and engineering, and was seen as a major hire for Uber as it sought to bridge the gap between the technology and automotive industries.
On moving to Uber, Marakby relocated from Detroit to Pittsburgh, where Uber's autonomous car division is based. He reported to Brian McClendon, the former Google vice president who headed Uber's mapping and business platform, before also leaving, in March 2017. Uber's head of communications, head of artificial intelligence and president of product and growth have also all left in recent months.
Marakby went on to play a key role in Uber's launch of its self-driving fleet, but has now parted with the company without saying where he will work next. "Self-driving is one of the most interesting challenges I've worked on in my career, and I'm grateful to have contributed to what will soon be a safer future for everyone," Marakby said in a statement.
Uber said in a statement: "Sherif's deep experience and knowledge of the automotive industry have helped us tremendously in working to make self-driving cars a reality."
The trials and tribulations of Uber's 2017 so far
This reports comes after months of bad press for Uber. The company began 2017 by coughing up $20m (£16m) to settle claims it misled drivers over earnings potential, then lost many users during the #DeleteUber social media campaign in the wake of President Trump's proposed immigration ban.
In February, Kalanick quit Trump's advisory board. A week later, Uber's autonomous truck division, called Otto, was alleged to have operated its driverless trucks on public roads without a license. A former Uber engineer then claimed her manager openly propositioned her for sex during her first day on his team.
This was followed by Waymo, Google's self-driving car company, suing Uber for allegedly stealing 9.7GB of documents relating to its autonomous vehicle technology, which Waymo claims Uber is using on its own cars. In late February a video emerged of Kalanick swearing at, and losing his temper with, an Uber driver. A month later, one of Uber's self-driving cars was involved in an accident which caused it to roll over. The autonomous fleet was withdrawn from service, but resumed work once it was established that the Uber was not at fault.
In April, Uber was banned from operating in Italy, then days later it was accused of secretly short-changing both drivers and customers in the US. Most recently, Uber's head of PR, Rachel Whetstone, quit the company.