I just got the unit yesterday and everything seems to be working fine as far as using the SD from the device. I've downloaded several games, youtube, etc. I just can't seem to access the card through Windows.
I get the username/password prompt, enter the info I entered on the 3DS. The 3dS says it is "Currently connected to a PC." In Windows Explorer I see the device and the microSD folder.
When I double click that folder, I get the following error in a popup:
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\\<my 3ds name>\\microSD is not accessible. You might not have permission to use the network resource. Contact the administrator of this server to find out if you have access permission.
The directory name is invalid.
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Any ideas?