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A am asking about problem with USB data stick (that uses fat32 file system).

If you unplug USB stick without unmounting (safly remove) data may become locked when you mount USB stick another time (you can't make changes to files). If you unmount and mount partition few times, data becomes normally accessible.

Problem is that I can not repeat (force) this problem now. But it has happened many times even recently. Has this been happening to someone else?

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Never had this happen.. –  djeikyb Feb 14 '11 at 22:18
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1 Answer

If you unplug a USB flash drive without unmounting it first you can easily have data loss.

The type of messages you are seeing is a reflection that the data is not clean and some of it is thus locked. fsck will fix these issues as well, but sometimes with data loss.

When mounting a file system the kernel prepares the file system for use, and when unmounting the kernel reverses the process including checking that none of the files are in use and that your data has been written to the disk (your data can be cached and not yet written).

See man sync, man fsck, and http://tldp.org/LDP/tlk/fs/filesystem.html for details.

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Hi! Thanks for answer. I think i had "bad" usb or filesystem. This problem does not occur again. Kernel probably remounted usb as read-only, which resulted as my problem. (any idea what to do with question?) –  gsedej Sep 10 '12 at 17:39
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