Topic: I'm having major issues with a micro SD card in my switch.

I have a 128 gig SD XC and I've been trying to download assassin's creed black flag. It starts out fine and even gets nearly finished then i get an error has occured message. I guess that means it's corrupted because i try to redownload and it instantly fails. I've reformatted several times and it keeps happening. Just a while ago it got to 90% and just crapped out on me again! I'm getting really frustrated. This card is about to go in the trash!

@Zeldafan79 did you format it on a desktop or laptop sometimes you have to use a laptop or desktop to format it, the format option on the switch console will not format it properly.

@Zeldafan79 I discovered last week..... Currently nintendo support (for north america region) only gives directions to format the card with the console. If you want to see directions for formatting with a computer, you have to find the page for How to Transfer Data Between microSD Cards for Use on Nintendo Switch.
https://en-americas-support.nintendo.com/app/answers/detail/a...

I can't help point out, when my micro sd card failed in my phone last summer, it was a gradual process. It started failing at doing big jobs. Then got worse, started failing quicker. If you plugged the card into the computer, you could still see all the files, but if you copied a large video file from the card, it usually failed at some point during the job. So, I will suggest, a failing micro sd card might possibly be a cause of your issue? But know that's a guess.

Based on your download issue, it might be tough to tell if it's just internet traffic with Nintendo's server, or your card, or something else(I won't pretend to know everything with troubleshooting). If the game won't fully download after leaving your switch in sleep mode over night, that could indicate something is wrong. But I know, doing an over night test sounds crappy when you just want it fixed.

If you talk to nintnedo, they will ask if your console is updated, and that there's no interference with wifi. Be ready for that if you talk to them.

Nintendo has a phone line and a chat messenger. It's pretty easy to get someone on the line there when I've called. Their phone menu tree is quicker than most companies. Just be ready to say "representative" if needed to talk to a person in tech support. https://en-americas-support.nintendo.com/app/contact

Okay thanks I'll try formatting from the computer instead. It seems to happen more often when I'm trying to download in sleep mode. My Wi fi signal might be getting interrupted. When my switch is in the dock i've noticed it loses the connection sometimes.