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How can I recover files encrypted with Windows filesystem encryption?

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Summary: The Windows encrypting filesystem ensures that only you can access your files. However if you lose your login account you could have a serious problem.

It all started some months ago when I changed the properties of most of my personal files to encrypted just because I thought they would be safe from hackers. Of course as I don't share my computer with anyone I could open and edit them all I wanted without any trouble. I never really thought that property was special in a functionable way.

Last week I took my computer to have a new hard disk added, in the new hard disk Windows XP was installed and my old data was kept in my other hard disk, remaining as a 'slave' (I think that's the term). Unfortunately my main and only user session was deleted. Now I'm stuck with an administrator user that can't change the properties of my files back to normal. I can't listen to my music nor edit my documents, I can't even view my pictures. I'm so sad, I don't know how to fix this. I fear that there's nothing I can do because, obviously, creating a new user with the same old name won't work as the files are now on my old hard disk and I can't move them to other location.

If there's any solution regarding this case, I'll be forever grateful. If the solution involves programming skills I'm counting on my boyfriend who knows about that stuff.

My gut reaction?

You are so screwed.

Sorry to be so blunt, but what you're experiencing is one of the major drawbacks of Windows' built-in encryption.

I'll throw out one straw to grasp at, but then I'll explain why this happened in the first place.

Here's my one straw to grasp at: if this were my machine I would restore it to its original configuration. By that I mean remove the new drive and set the old drive to once again be the only drive and boot off of that. If the drive hasn't been altered, then you may be able to then login with your old account and access your encrypted files.

If it turns out you can access them then back them up. Now. More on that in a second.

"The greater chance is that you're SOL: Severely Out of Luck."

If not, things get much more complicated, and I'm not at all hopeful that you'll be able to recover. Have your boyfriend or a technician check out the Microsoft information on the encrypting file system, paying particular attention to the section on recovery. It's highly unlikely, but if the correct encryption keys can somehow be recovered there's a slim chance. A very slim chance.

The greater chance is that you're SOL: Severely Out of Luck.

So why is that? What happened?

The key, both literally and figuratively, is that when files are encrypted in Windows using the encrypting file system they use cryptographic keys that are associated with the login account that created them. So if I'm logged into my machine with a user account "Leo" and mark some files as encrypted, then those files can only be decrypted when I'm logged into that "Leo" account.

The gut reaction when the login account disappears or is somehow inaccessible is to create a new account with the same name. In other words if my "Leo" login account disappeared, I'd just create a new account with the same name.

Doesn't work.

You can create the account with the same name, but it will not be able to access the files encrypted under the previous account named "Leo". Even though they have the same name, they are still two different accounts. The cryptographic information associated with each is different.

If the cryptographic information for the account that created an encrypted file has been lost then there's simply no way to recover the data.

You're SOL.

I know that you used encryption on a lark, and that's fine. Presumably this has been an "interesting" lesson learned.

For those that really are looking to encrypt data, the problems that I've described here are reasons that I never recommend using the encrypting file system. It's simply too easy to inadvertently lose your data. In my opinion it also doesn't really provide all the security you may think. Anyone can walk up to your machine while you're logged in and access your data, encrypted or not. That may be enough and you may handle your physical security in such a way that that's not a risk, but it's easily overlooked.

My recommendation is a tool like TrueCrypt. You can set up virtual drives containing encrypted data that you use just like any other drive or filesystem. The encryption is tied only to a password or passphrase - as long as you have that you can recover your data, no matter what machine it's on or where it's located. TrueCrypt also supports auto-dismount under various circumstances that can protect against the walk-up access I mentioned above.

If you do end up using the encrypting file system, make sure to understand and follow the recommendations for backing up the cryptographic keys. With those keys it should be possible to recover encrypted data.

Lastly, and speaking of backup, all of this could have been a non-issue if you had been backing up your data regularly. Imagine if your hard drive had simply and irreparably died. Encrypted or not all, your data would be lost.

Unless, of course, you had a backup copy of it all.

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Article C3191 - October 24, 2007

Recent Comments
12 Comments

"Have your boyfriend or a technician check out the Microsoft information "

My goodness Leo, I am normally not sensitive about such things, but this certainly seems to be a sexist comment. Why does one have to be male to understand Microsoft information? Is it written in a secret(male)language?

On the whole, I enjoy your site and find it informative and interesting.

Posted by: Judith Currier at October 27, 2007 4:16 AM

Judith,

He suggested she ask her boyfriend because in her letter she wrote if this involved
"programming skills" she would ask her boyfriend because he "knows about that stuff". Whether she's speaking of programming languages or normal computer tech skills who knows.

Posted by: Josh B at October 27, 2007 10:26 AM

Actually I have encounted the same problems before. I use the knowledge from NT Server 4 to perform on the Windows XP Pro with the old system drive as the slave. You only have to reassign the encrypted files rights back to the system. Once the files are own by the system, create a new user and reassign all the files right to that new user. Login as that new user and you are already accessing your files!

Posted by: ena at October 27, 2007 3:36 PM

There is a method that you did not even suggest and it is so simple that you would freak. True security on any computer is very difficult too acheive (not imposible) You can talk to the security experts to find out how simple it is.
I do this on a regular basis and I do not want to give it away.

Posted by: Oliver Galea at October 29, 2007 5:09 AM

I have encrypted my file and after that i changed my operating system.After that when i try to open my encrypted file,it didn't open.Said "Access is Denied".You have no Permission,I have tryed so much but i cant open the file.
Please I request to u Tell me some idea from which i could access my file. Bye..........

If you used Windows built-in encryption, then it's likely that you're out of luck. See the article - it needs to be opened from the same user account, which was probably wiped out when you installed another OS.
- Leo
01-Nov-2008

Posted by: Ranjit Goswami at October 31, 2008 1:17 AM

I had the same situation, I had encrypted a folder containing more than 3GB data and when last week I restored my system drive from an image file, I found myself in a real nightmare: I could not able to access my old data! f..k you Microsoft, I told many times, after many hours searching, I come up with a great tools called Advanced EFS data Recovery, it saved my life. Its last edition can found any private key (you need them) from disk clusters (where that your last windows still stayed there) and decrypt your folders. It is very strightforward.

Posted by: reza at April 17, 2009 6:10 PM

I just attempted to copy encrypted folders (and contents) to an NTFS USB drive using an Ubuntu Live CD. It would NOT copy the files. I will re-test with a FAT32 USB drive and see what happens. Ubuntu is of course a Linux based OS.

Posted by: Joe at April 18, 2009 1:46 AM

Oliver Galea said in his post that recovering encrypted files is "so simple you would freak". Perhaps he is referring to this method of freezing the DRAM chips with liquid nitrogen?
http://www.disco-tech.org/2008/02/stealing_encrypted_data.html

Posted by: Joe at April 18, 2009 1:09 PM

I have encypted a file that was actually hidden. And the file name was " " which means I renamed it " ALT 0160 " when you name a file this way nothing shows in the name space. + The file icon was invisible. Now I cant find my folder ): any clue ?

Posted by: Saeed at May 10, 2009 7:09 AM

I've moved D drive folder files as new folder by using admin account called 'Admin' afther that i'h created a new admin account called 'Hk admin' and i'd delete the previous account using Hk admin account. After that i cannot open any document. And i cannot move or copy any file in the foler to any thing. And cant remane aslo. After that i'h restored the pc as previous date. But also in the folder any file can't open and copy or move, rename. So please tell me how do i back can back to normal my files. Pls that is very important files i cannot open it. Pls help

Posted by: Mohamed at August 30, 2009 3:23 AM

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