Williams have been forced to cancel running on the final day of the first pre-season test because of damage sustained in a crash on Wednesday.
Williams discovered a chassis had been damaged when novice driver Lance Stroll spun into the barriers.
That meant his team-mate Felipe Massa was unable to take part on Thursday.
Williams said they would make repairs and "aimed to be back on track" for the start of the second and final test on Tuesday.
Stroll's accident was his third off-track moment in two days. The 18-year-old Canadian is making his debut in F1 this season and is bringing considerable financial backing to the team, said to be at least £20m this year.
That is in addition to a similar amount last year, when the team provided him an extensive test programme in a two-year-old car at circuits around the world to prepare him for his debut.
But he has had a torrid introduction to F1 in Spain this week.
On Tuesday, his first day in the 2017 Williams car, Stroll crashed at the high-speed Turn Nine after just 12 laps and damaged the front wing.
Williams had to stop running for the day while the wing was sent back to their base in Oxfordshire for repairs and a new one was flown out for Wednesday.
Stroll then completed 100 laps before crashing again at Turn Six.
Williams engineering chief Rob Smedley said Stroll had been caught out by the lack of grip on cold tyres.
"They are good to lean on them, but there is a certain point where they become very tricky," Smedley said.
"Lance was out on cold tyres, on an out-lap with a lot of fuel in the car, and the tyre stepped away from him.
"He was an innocent victim of that happening and what should have been an innocuous sideways moment brought him around into the barrier and did some damage. That happens and we expect it to happen - there is no blame on his part."
The other nine teams started their running on Thursday on a track that had been artificially soaked for a wet-weather tyre test.
The first test finishes at 17:00 GMT.