A hiccup in Tesla’s latest over-the-air update caused several owners to lose all functionality of their vehicle’s semi-autonomous driver aid system. Tesla told one driver it’s a “known issue” internally and a fix is expected by Friday.

Tesla’s cutting-edge ability to send fixes remotely to vehicles has earned the company praise time and again, from being able to to its () ability to extend the mileage of vehicles for owners trying to escape a hurricane.

The electric automaker has been pushing out its latest, anticipated over-the-air software update throughout the week to its vehicle fleet. The update is intended to increase the capabilities of Autopilot to include on/off ramp maneuvers, and improve recognition of traffic lights, stop signs, and lane changes.

But for now, several Tesla owners report they can’t even use Autopilot, after the latest update failed to install in their car.

“This is a currently known issue and our engineer team is hard at work resolving the problems that have occurred,” a Tesla employee based in Fremont, California, where the automaker’s factory is located, wrote in an email this week to one Model 3 owner.

The owner, who spoke on condition of anonymity, told Jalopnik they took deliver of their Model 3 earlier this year, and after the software update failed Tuesdaynight, they spoke to a Tesla rep who said it should be fixed Wednesday.

But then they discovered Autopilot had been disabled. The driver said it took nearly a half hour to reach a rep by phone, who explained there was no “immediate fix” but that it should be resolved “soon.” After another hour and a half on the phone waiting to hear back an explanation for the issue, a Tesla rep explained by phone, and then in an email, that a fix should be forthcoming.

“The current estimate is that the issue should be solved in the next two days,” the email said.

The issue represents the latest in a string of complications for the automaker, which lost several top executives in recent days amid a maelstrom created by CEO Elon Musk’s bungled attempt to take the company private. In May, Tesla over the sluggish rollout of its updated Autopilot system, Tesla owners pay $5,000 to add Autopilot to their car.

It’s unclear what caused the issue, how many vehicles are affected, and if it’s hitting just Model 3 owners or Model S and X owners, too.

A Tesla spokesperson didn’t have an immediate comment when reached late Wednesday by Jalopnik.

Several owners, in posts on the , confirmed they’ve also experienced a complete loss of Autopilot as a result of trying to launch the latest update.

“I called and they said yea a lot of people are getting this, wait for another update in a few days, you can still drive on it,” wrote user pazdan. “OK, so I drive and notice no autopilot ability.” The update failed twice more, the post said, and the driver had to schedule an update to bring the car in next week for an examination by an engineer.

Another user named “Zaxxon” said on Wednesday that after the update failed, his monitor showed a “persistent ‘update required, contact Tesla service’ message, and Autopilot is non-functional.”

Yet another driver said on the forum that they tried to apply the update on Tuesday, but it failed and the car notified them to contact the service center.

“And my AutoPilot didn’t work,” the user, krettig, said. “So I called the Service Center, they sent down another update. I tried to apply it, but it also failed. My autopilot still doesn’t work, but I’m getting messages that Emergency Braking, Regenerative Braking, and Traction Control are not working.”

“I called Tesla again and they said they are working on a fix and will push it out as soon as they have it ready,” the post went on. “Might be a few days. I hope I don’t need emergency braking or traction control in the meantime.”

Tesla’s already dealing with a frenetic week, after Musk confirmed on Wednesday that customers may experience “longer response times,” due to a “large increase in vehicle delivery volume in North America.”

Musk tweeted early last month that he had “funding secured” to buy out every share of the company’s stock and take it to private. , Musk’s haphazard tweet sparked off a SEC probe and several securities lawsuits. In that time, several executives have left the company, including Chief Accounting Officer Dave Morton, who resigned after just one month on the job, “the level of public attention placed on the company.”