Early reviews of the Nintendo Switch have noted occasional connection problems with the Joy-Con controllers. Fortunately, it appears that Nintendo is aware of the problem and has provided instructions on what to do. All you have to do is not operate the Joy-Cons near aquariums, microwaves, or just about anything with a wireless connection.
According to the support page, Nintendo believes that electronic devices could be interfering with the Joy-Con connections. Preventing them from pairing correctly with the Switch console.
The instructions advise players to put the console out in the open to minimise interference. For some reason, the same set of instructions specifically call out placing the Switch near an aquarium as something that could cause interference. It’s high enough on the list to make it more important than placing it near another wireless device.
Speaking of which, Nintendo also advises users to keep the Switch at least three to four feet (about 1 metre) away from other wireless devices. These include laptops, tablets, wireless headsets, wireless speakers, cordless phones, and USB 3.0 compatible devices like hard drives and LAN adapters. Microwaves are also curiously included here.
To be fair, microwaves are known to cause large amounts of electro-magnetic interference. It’s no surprise that the Joy-Cons are adversely affected by someone using them next to a microwave. The aquarium is still a mystery though.
That’s not to say that the Joy-Cons are completely worthless in a home full of electronics spewing wireless connections. It’s simply that some people have reported that this happens, and Nintendo is providing them options for resolving the problem.
[Source: Nintendo Support]