I just got a new 8GB microsd card and a micro-mini adapter, pushed it in, and nothing happens in my N810. Is there a specific action i need to take to make it recognize it?

thanks in advance

It should work straight away. I have a 8GB micro, and it works fine.

Did you try it in another card reader to see if it works there? Does your n810 read other cards ok?

Please, to assist others in the great quest for quality products, post brand and source.
For instance some 8Gb Sandisk micro's thru various sellers at Amazon have been purported to be fake, based on the marking of the cards versus that on the Sandisk website,

compare
http://www.sandisk.com/Products/Prod...o.aspx?ID=2675
versus
http://www.amazon.com/gp/product/B00..._luc_sbs_02_02

note the arrow in the upper left corner of the one thru Amazon versus the speed in the @ symbol.

You might want to reseat the microSD card in the Mini adapter. Mine doesn't recognize it at times after pulling it out, but reseating the card in the adapter fixes it all the time.

And don't forget to close the memory card door, or it won't work.

Yeah, first make sure the card is all the way in the adapter, then that the adapter is all the way in the slot. It clicks in, and needs to be pushed way further than you think.

Second, try a search. This is a relatively common problem, which I too am currently experiencing. The thinking from what I've read tends to be that it's a combination of the adapter and something about the N810 that makes it not work with adapters that may work ok for other things. It seems to be exceedingly finicky.