Starbucks (NASDAQ: SBUX) is in the middle of a significant turnaround effort. The business has been struggling to grow its sales in recent quarters, and that has created worry among investors. The situation has been concerning enough that the company has brought on a new CEO, Brian Niccol, who is looking to get Starbucks back on the right path.

While the stock surged earlier this year on news that Niccol was joining the company and leaving Chipotle Mexican Grill to do so, a change in leadership doesn't mean that it's going to be smooth sailing for Starbucks. In fact, there are signs that this could be a considerable challenge, even for Niccol. And you don't have to look much further than the company's recent earnings numbers for evidence of that.

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Starbucks' turnaround may not be quick or easy

While new CEO Niccol is attracting a lot of attention from investors these days, it's what the company's chief financial officer, Rachel Ruggeri, said recently that shouldn't go unnoticed. Ruggeri suggested when discussing the company's latest quarterly results that the company is having some challenges in turning things around. "Despite our heightened investments, we were unable to change the trajectory of our traffic decline."

There have been complaints that the ordering process at Starbucks hasn't been ideal and that perhaps the environment isn't as welcoming as it was in the past. Niccol is also focused on simplifying Starbucks' menu. There are opportunities for improvement, but the big takeaway from the CFO is that there doesn't appear to be an easy fix here. Ruggeri says that "we are developing a plan to turn around our business, but it will take time."

Guidance suspended and plenty of uncertainty ahead

In another sign that management is uncertain of the path forward, Starbucks also announced that it was suspending its guidance for fiscal 2025, which ends in September. For the most recent quarter, which ended on Sept. 29, the company's global comparable store sales declined by 7% -- that's even worse than the 3% decline Starbucks reported a quarter earlier.

Changing the ordering process and simplifying the menu may not be enough to fix Starbucks' problems. And with the company being a large global brand, there are many geopolitical factors to consider as well. The conflict in the Middle East, for example, has been a reason for some consumers to boycott the coffee company for its perceived connections to Israel. And in China, Starbucks faces growing competition and pricing pressure.