NEW YORK ( MainStreet) — Everything about your 401(k) is going along just fine — you've selected your funds with care, contribute all you're allowed, get the boss's full match and avoid damaging moves such as borrowing from the account. Then, all of a sudden, you're thrown a curve: Your company switches to a new provider.

What now?

In a perfect world, your company has a good reason for the switch, such as reducing fees or improving the plan's offerings. But in the real world, the change may, for one reason or another, be better for your boss than for you. Or a new plan that is perfectly good for most of your coworkers might not suit you as well as the old one.

In any case, a change in provider means you should to a little sleuthing to make sure there have been no glitches in your account and that your new funds are the ones you really want.

"If your company is changing 401(k) providers, you've probably been assured that the transition will be seamless, and from a superficial standpoint, it may well be," says Christine Benz, director of personal finance at Morningstar, the investment-information firm.

"The new 401(k) provider will work with your firm's payroll manager to make sure that contributions flow into the plan right on schedule, and your elections -- both contribution amounts and investment choices -- should also carry over to the new provider without you having to lift a finger."

Still, she says, you should check your new statements to be sure they reflect the full amount that should have been transferred from the old plan. Be especially attentive if you've been making contributions to a Roth account as well as a traditional account.

In retirement, the Roth withdrawals will be tax free, while those from the traditional account will be taxed as income, so mistakes could be costly. Be sure your new contributions are for the correct amount and are being divided between these accounts correctly. The same goes for any after-tax contributions you'd made.

Next, make sure the new plan has recorded the correct beneficiaries — the people who will inherit your account.

Then, of course, you need to be sure the new funds suit your strategy. Typically, the new provider will select funds that are similar to your old ones. That's easy if, for example, you'd been investing in funds that track indexes such as the Standard & Poor's 500 . But some funds that look comparable might be quite different.

Suppose, for example, you'd invested in a target-date fund designed for a retirement starting in 20 years. Your old provider might have a large stock allocation after that target date arrives, while the new one might be more conservative. You need to know.