Windows Phone 7 was unveiled yesterday to much press and fanfare, and now that everyone has had a good chance to examine the OS and the devices that it runs on, all of its intricacies are coming out.  One of the biggest, and most interesting, aspects of WP7 is that the OS won't work properly if the user swaps in an SD card different from the one that the phone shipped with.  According to Microsoft, Windows Phone 7 uses a "special, high-performance SD card" that is different from regular cards.  When a phone is first set up, its internal storage and SD card are combined to form one storage system.  If you put in a different SD card, Microsoft says that your Windows Phone won't work properly and data could be erased.  It's important to note that not all WP7 devices will include an SD card slot, but there is at least one launch device that does sport a micro SD card slot: the Samsung Focus.

This is pretty big news, and definitely something to consider if you're thinking about picking up a Windows Phone 7 device.  While most users will be content with the 8 or 16 GB of memory included with many handsets, others could have larger media libraries that they may want to put on their phones.  Sure, WP7 does a lot of cloud streaming and storage, but not being able to swap out SD cards is kind of strange.  Does the news of having non-expandable storage put any of you off of Windows Phone 7, or are you willing to overlook it in exchange for all of the OS's other features?

UPDATE: It looks like Windows Phone 7 does support expandable storage after all.  The catch is that if you want to use a new SD card, you'll have to perform a hard reset on the device to allow the new card and the internal memory/OS to combine.

Via IntoMobile, Microsoft, Windows Phone Secrets