Photographer Gil Lavi has started having major problems with his Leica M9 — and he's not the only one. In a blog post Lavi lays out how his shiny new Leica has not been playing well with SanDisk memory cards. The SanDisks caused the camera to crash and be useless until they were pulled out, and making the SD card itself unreadable. He even tried replacing his M9, only to find that now it wrote to the disks at a glacial speed, and produced 0KB image files.
Initial problems were due to the use of low end cards which in your case is not the case! Low end cards often do not conform with the standards of hight end SD cards, which can lead to problems.
Therefore the problem that you are describing was initially an isolated issue that was resolved by formatting any new card to the FAT standard after San Disk issued cards with a new card format.
In the meantime we have learned of your problem and others with the same issue, which made us look into into it.
So, for now it seems that they're saying to make sure that disks are FAT formatted.
In other Leica related news, if you think your M9 is a bit ostentatious, what with its large red dot and all, you can pay to upgrade it to an M9-P. The upgrade comes in two flavors: for $1,295 there's the “Sapphire Glass” pack, which replaces the LCD screen with a tougher, sapphire-crystal cover, a choice between vulcanite and smooth leatherette trim, and a one-year warranty extension. The $1,995 “Top Cover and Sapphire Glass” does all of the above, but also swaps out the top and bottom plates for the more subtle version seen on the M9-P, available in silver chrome or black paint.
$2000 is a pretty penny for what essentially amounts to a paint job, but given that it's Leica, we're not that surprised.