On June 19, 2011, we had a software bug that caused authentication issues. You can read more about it in our blog post. Our records show that your account wasn't improperly logged into during this time.

We are writing to you because one or more users you share a Dropbox folder with logged into their account during that period. We have no reason to believe that the login was improper, but in the unlikely event it was, there could have been access to the information in the following shared folder:

<folder>

We are very sorry as this never should have happened. We are implementing additional safeguards to prevent this from happening again. If you have any questions please contact us at [email protected]

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Note that Dropbox says the account was not improperly logged into != illegal activity (file copy/delete using stolen tokens) as they follow by admitting that they have no way of telling if a shared folder has had improper access.

It can't be both...