He compared the company to a maritime first that ended poorly.
"The bet that investors are making today is that they're going to have this ship turned by Christmas," he added. "I don't think that's possible. I think that it's the Titanic heading for the iceberg. It's going to take probably two or three years to turn this ship around, and they're going to crash into the iceberg before they can get it turned around."
Pachter has a "sell" rating and a $9 price target on Best Buy stock.
In a separate interview on CNBC's "Squawk Box," Michael Lasser, hardline retail analyst at UBS, was more bullish on the company's turnaround and said the company's showrooming issue had been overstated.
"What they showed in the fourth quarter was that they put forth a good first step in what's going to be a very long transformation process from a new management team that seems to understand where the problems are," Lasser said.
Lasser added that it has taken the company a while to figure out how to transform into the future of retail.
"I think what we're going to see from Best Buy over the long term is an evolution where their stores become a focal point to launch their online business and really have a true omnichannel offering for consumers," he said.
He cited one challenge for the company: founder and former chairman Richard Schulze, who had until Thursday to submit a buyout offer to take the company private. Best Buy said it did not receive an offer.
"I think the challenge here is that the founder still owns 20 percent of the company, and there's a chance he's not going to want to stick around without managerial or economic control," Lasser said. "This could be a perpetual pressure on the stock and could be disorderly if Schulze decides to sell all at once," he added.
—By CNBC.com's Katie Little; Follow on Twitter
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Michael Pachter does not own shares of Best Buy. UBS has an investment banking conflict with Best Buy and owns stock in the company.