Yes it's quirky and receiving wrong sizes in Win isn't a good sign, as i said it's a flaky unit. But if you can't access MSM how did you check the freespace in Win? The only other way i know is in Disk Management where freespace will show even without a drive letter, maybe you just need to allocate it one? However, I still believe you should re-format it and only put back known-good files even if you find it only needs a drive letter. If it's not so simple as a missing letter and you don't want to flash cure fw and reformat, It might last forever like it is or die tomorrow, who knows .... I guess you can keep accessing it in Linux and take the chance but i wouldn't, your call.