“It had a handful of what I’d call acceptable tech glitches early on, like the falcon-wing doors not always detecting that I was ready for them to open,” explains Deeter, a partner with Bessemer Venture Partners. “But in the past couple of days it’s gotten to where I think there are safety and usability issues.”

Deeter’s first problem was that the driver’s door wouldn’t open from the outside, prompting him to first open the passenger door and then reach across. Then the driver’s side door wouldn’t close.

“I could manually close it, but the car couldn’t sense that the door was shut, so the electric control wouldn’t latch,” says Deeter. “Yesterday, I literally drove to a meeting holding the door closed.”

Deeter later power-cycled the system, which cured the problem until he got back in the Model X this morning. He resigned himself to another day of driving with one hand on the driver’s side door, but as he backed out of his driveway, the emergency brake kept automatically engaging. He’d drive a few feet, be forced to stop, put the car in park and then reverse … before the entire thing began again. And, to make things even worse, the driver’s side window would no longer close all the way.

“It think all of this is theoretically a software issue, but maybe it’s combination of that and the sensors also failing,” says Deeter, who has made early investments in such tech companies as Box (BOX) and Cornerstone OnDemand (CSOD).

There does not appear to be any roadside assistance option on the car’s computer, so Deeter sent emails to three different customer service addresses listed on Tesla’s website. The first email was sent after yesterday’s troubles and, as of 12 hours later, he still had not received a reply. So he followed up with a phone call, but was told that Tesla is booked up for service issues through the third week in May.

To be sure, Deeter is not the first to have problems with the Model X. Consumer Reports on Tuesday reported that Model X owners are flooding message boards with complaints, particularly related to the falcon-wing doors doors—sending the company’s shares down more than 2% (it has roared back in Wednesday trading). And that doesn’t even address an earlier recall of select Model X vehicles, due to an issue with its third row of seats.

A Tesla spokesperson was unavailable speak with Fortune, but did email over a statement that said, in part: “We have seen an outpouring of excitement and satisfaction with Model X and are grateful to our customers who have worked closely with us to bring any issues to light. Because of them, we are quickly implementing fixes and have made significant improvements to Model X builds moving forward.”

The spokesperson did not respond to the customer service issue, which is at odds with the company’s general reputation.

Deeter says that he remains a big fan of Tesla and believes that within five years we’ll be able to summon autonomous vehicles via mobile apps. But, he adds, “this is a huge reminder that 99% complete software isn’t sufficient when it comes to moving people.”