The Red Devils have lost three of their first five Premier League fixtures and sit in 13th place.
Neville believes the Glazer family is to blame for the rot that is continuing to set in at Old Trafford.
He has now called on the Americans to sell United as quickly as possible to allow a reset of the club from top to bottom.
“Oh, and yes, the Glazers are responsible. It’s how it works. You own a business, and everything good and bad sits with you! They inherited the best in all areas. They’ve overseen 10 years of mediocrity off and on the pitch.
“They set the culture of greed, ill-discipline, indecision, and uncertainty that runs right through the club. It would be best if they sold the club with some speed and efficiency and allowed at least the off-the-pitch items to be corrected properly that reset the tone and culture,” Neville tweeted.
The Red Devils take on Bayern Munich next in the Champions League.