Of the first generation Windows Phones, the Samsung Focus was the only one that had a readably accessible MicroSD slot for memory expansion. The problem of course is that neither Microsoft or Samsung necessarily encouraged users to add memory to these phones and the results were mixed at best.
Having done some serious working on this over the course of the past few months I have come to some conclusions that I hope will help you if you decide to try to use the MicroSD expansion. I’ve classified this post as a How To but it is really more For Your Information than anything else.
The first thing in all of this is the MicroSD card itself. I’ve tested Kingston, Parrot and a generic card so brand isn’t really an issue. The key is the Class of the card which needs to be a Class 4 in this case. Every test I did with a Class 2, Class 6 or Class 10 failed. The phone never recognized the card. Every Class 4 card I tried worked.
Second, if you simply put the card in your Samsung Focus it will give you a warning telling you that the card is not recognized and to power off the phone. The trick here is that you have to do a hard reset with the card in the phone for it to be formatted and recognized. I posted here how to hard reset a Samsung Focus by just using hardware keys, something you will need to do in this case. Once you do this hard reset the card will be recognized.
Third, somewhat goes without saying but you are going to have to do a hard reset of your phone so make sure you have any data you need backed up or in the cloud (Skydrive, Dropbox, etc).
Finally, once you put the card in your Focus, do the reset and format the card, it is essentially married to your device. If you take the card out you will have to do a hard reset again to get things back to normal. When you format the card it becomes a part of the memory system for your Focus. Removing it does bad things so don’t unless you absolutely have to do so.
The benefit of all of this is of course the added memory. The Focus comes with 8GB of storage but mine has 24GB thanks to the 16GB Kingston Class 4 card I have in my phone. If you want to get this card, here is the Link on Amazon
I do not promise or guarantee this will work on your Focus. There have been plenty of issues with people trying to expand the memory on this phone and it not working. Do this as your own risk.
[Update] – Twitter follower @aqcohen tweeted to me, “I’m using a 16GB SanDisk microSDHC Class 2 working without a problem.” This is good to hear. I was only able to get Class 4 disks to work!