This question is prompted by my finding hundreds of e-mails that I thought I had deleted still on my web-mail. So I followed instructions to put them in Trash and to Empty Trash. Are they now absolutely irretrievable, or could someone who didn't care about time or money, in principle, get them? (Is everything ever sent retrievable, in principle?) I am not worried, merely curious. The web-mail even asked me, rhetorically: "Why delete anything when you have so much storage space?" Deletion seems to be against the mores of the computer world.


closed as off-topic by J.-E. Pin, David Richerby, vonbrand, Juho, Nicholas Mancuso Aug 4 '15 at 23:52

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question does not appear to be about computer science, within the scope defined in the help center." – David Richerby, vonbrand, Juho, Nicholas Mancuso
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ On the macroscopic scale (i.e. relativity) according to what little physics I understand, it possible in principle to determine the state of any close system arbitrarily far in the past. Basically as long as decoherence is taking place this is in principle possible. $\endgroup$ – Jake Jul 25 '15 at 2:54
  • $\begingroup$ Can you explain in more detail what you are trying to ask? Most systems, from what I remember, when erasing securely, write all 1's (or 0's) the corresponding bits of the items being deleted on the disk drive. $\endgroup$ – Ryan Jul 25 '15 at 3:46
  • $\begingroup$ Web-mail means that the data is kept on a server somewhere. What "clean thrash" over there does is anybody's guess... $\endgroup$ – vonbrand Jul 25 '15 at 21:55
  • $\begingroup$ This is not a question about computer science, or computers for that matter. $\endgroup$ – vonbrand Jul 25 '15 at 21:57

The answer depends upon how the webmail service is implemented, and whether it tries to delete all copies of the email. As one example, if the webmail service keeps periodic backups, the email might still be present in the backups. As another example, a webmail service could implement "Empty Trash" to hide your email so it won't show up to you, but is still stored somewhere (e.g., so they can continue to profile you and show you advertising). Without knowing how the webmail service is implemented, you probably can't know for sure whether the email is retrievable or not.

Of course, the sender and any other recipients will still retain a copy of the email, so in practice that will usually be one way that a copy of your email could be retrieved.

  • $\begingroup$ Thanks. This is the level of answer I was looking for, not the more physics answer. So, when I followed instructions to "Empty Trash", I emptied e-mails into another trash bin, one that I had no access to and that I will never see, but which is easily accessible to people who want to sell me things. The e-mail is retrievable to hucksters. Great. Understand, I don't want ever to see the ^%$#@* rubbish again, but I wish the ^&*%$# rubbish were changed into pure noise. $\endgroup$ – ab2 Jul 25 '15 at 6:31
  • $\begingroup$ @ab2, Thanks; I'm glad that helped you. To accept an answer, click the checkmark to the left of the answer. However, I encourage you to wait a day or so, in case you get another better answer. It's described at cs.stackexchange.com/help/someone-answers and meta.stackexchange.com/q/5234/160917. $\endgroup$ – D.W. Jul 25 '15 at 6:45

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