Even with the Honda era over, the British team remains in crisis; at Paul Ricard, there is talk of a staff revolt, the intervention of former boss Martin Whitmarsh, and a scandal farcically known as 'Freddo-gate'.
On top of that, Spaniard Alonso says that the orange car is simply "slow".
"The problem? The car is slow," he told reporters.
"It's the same car as the last three or four races. There is no problem with balance, it's just not fast enough. We go backwards - in each race we are less and less competitive."
The next problem for McLaren could be the loss of Alonso, with the Spaniard looking at Indycar and the team admittedly in talks with Daniel Ricciardo for 2019.
Alonso says that he is at least happy with his personal performance.
"I think I'm the only one who is 8-0 [in qualifying] against a GP3 champion, GP2 champion. All the categories in which [Stoffel Vandoorne] ran," he said.
"But this is Formula 1. You need the right package."
McLaren executive Zak Brown moved to downplay the current 'crisis', insisting that the team is not on the verge of losing a swathe of staff members.
"I can confirm that all members of the racing team will remain with the team until the last race in Abu Dhabi," he insisted.
However, he admitted that McLaren has "aerodynamic" problems, and is currently using the Toyota wind tunnel in Cologne to fix them.
"The Toyota tunnel works well but it does not simulate everything or show all of the problems," said Brown.
"We don't yet have the solution to the problem so we are not focused yet on the car for next year but rather trying to make sure that these problems don't hurt us in 2019 as well."
As for the staff revolt and the intervention of Whitmarsh, Brown said: "He's unemployed so I guess he's looking for a job somewhere. But he's not going to get one at McLaren."
McLaren are fifth in the team standings with 40 points going into this afternoon's French Grand Prix.