USB Storage - deleting files

[Mumia W.]

On 09/17/2008 12:30 AM, Chris Jeffries wrote:
> On Tue, 2008-09-16 at 22:23 +0100, ubuntu-users-request at lists.ubuntu.com
> wrote:
>> Re: USB Storage - deleting files
> 
> Thanks for the comments guys. All are worth remembering. However I would
> still like to know how the device got to be read-only, and how
> connecting it to a Windows PC cleared the fault.
> [...]

That happens when some devices generate write errors. In some cases, the 
kernel will flag the device as read-only to prevent any further damage. 
Unmounting and remounting the device clears the read-only status. 
Although unplugging the device is more radical than unmounting it, the 
effect seems to be the same.

Your USB stick just happened to have a write error while you were 
deleting from it. The error's timing was just a coincidence.