EFS, and why you shouldn't ever use it!

Mike Halsey MVP
Sep 11, 2011
Updated • Nov 28, 2012

Yesterday I wrote here about the BitLocker security file encryption system that was introduced with Windows Vista.  BitLocker is a full-disk encryption technology but I also alluded to problems with Microsoft's other encryption technology, EFS (Encrypted File System).  EFS has been with us for over a decade now and has slowly been improved by Microsoft.  I believe that it's an extremely good idea to encrypt your files and data, especially if you have a laptop, but certainly anything personal or financial on your main PCs if at all possible, or to at the very least make your PC secure with a strong password.

I would never recommend anybody ever use EFS however and here's why.  I'm extremely good with backups, I tell people all the time to make sure that they have adequate backups of their files and documents and I practice what I preach.  I use Windows Live Mesh to synchronise my documents, music and pictures between my main desktop and my laptop.  My main desktop then backs everything up to a second internal hard disk and also an external NAS (Network Attached Storage) drive.  I then have a secondary NAS drive which I keep off-site which I bring back every month or so to update the backup on that.  This is the way I recommend everybody does backups; though USB hard disks are just as effective as NAS drives and much cheaper.

I've lost files that I've backed up with EFS however, not only on my own computer but also on the NAS drives.  In fact I've only used EFS twice in the last ten years on my own computers and on both occasions I've lost files and documents.  I therefore cannot recommend you ever encrypt your files with this Windows feature.

The problems occur because EFS will encrypt any file that resides on an NTFS formatted disk, the default formatting option for XP, Vista and Windows 7 and also for the vast majority of USB hard disks and some NAS drives.  Unfortunately, because of incompatibilities with some differing versions of EFS files can end up scrambled and unrecoverable.  This wouldn't happen on a USB hard disk but I found it occur on my NAS box.  This means that if something goes wrong and you need to recover the backup from the drive, even the appropriate EFS key, that you would clearly have backed up and kept safe, won't unlock the files.  They will simply be lost and gone forever.

There's no way to know on what devices the EFS file scrambling will happen either.  With non-EFS supported devices, ie those that aren't formatted with NTFS, Windows will ask if you "want to copy the files without encryption" and will decrypt them on the fly.  Unlike BitLocker however, which just encrypts the hard disk, EFS encrypted files remain encrypted when copied off the machine to another NTFS formatted disk.

There are other problems with EFS too and these include metadata.  The EFS system, for reasons I've never been able to ascertain, is incompatible with the metadata you add to certain file types, pictures and photographs especially.  Not only will it strip out the metadata from these files, it will modify the files in such a way as to prevent you from adding the metadata back in afterwards, effectively making the file useless to you if this is how you like to organise your photos and pictures.

All of this comes from my own personal experience and it shows how even technical experts can be caught out by hardware and software incompatibilities and faults in, seemingly secure Windows features.  I would not recommend you ever use EFS.  If you have a laptop or desktop machine with a TPM chip and a copy of Windows Ultimate or Enterprise, use BitLocker.  If not the excellent TrueCrypt is a free utility that comes highly recommended by security experts worldwide.


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  1. Dan Donx said on January 15, 2023 at 10:29 am

    What mental age of reader are you targeting with the first sentence? 10?

    Why not write an article on how to *avoid* upgrading from W10 to W11. Analogous to those like me who avoided upgrading from 7 to 10 for as long as possible.

    If your paymaster Microsoft permits it, of course.

  2. Dexter said on January 15, 2023 at 11:14 am

    5. Rufus
    6. Ventoy

    PS. I hate reading these “SEO optimized” articles.

    1. cdr said on January 15, 2023 at 3:32 pm

      I used Rufus to create an installer for a 6th gen intel i5 that had MBR. It upgraded using Setup. No issues except for Win 11 always prompting me to replace my local account. Still using Win 10 Pro on all my other PCs to avoid the bullying.

  3. sv said on January 15, 2023 at 6:40 pm

    bit pointless to upgrade for the sake of upgrading as you never know when you’ll get locked out because ms might suddenly not provide updates to unsupported systems.

    ps…. time travelling?
    written. Jan 15, 2023
    Updated • Jan 13, 2023

    1. Martin Brinkmann said on January 16, 2023 at 5:49 am

      This happens when you schedule a post in WordPress and update it before setting the publication date.

  4. Anonymous said on January 16, 2023 at 8:24 am

    Anyone willing to downgrade to this awful OS must like inflicting themselves with harm.

  5. basingstoke said on January 16, 2023 at 11:18 am

    I have become convinced now that anybody who has no qualms with using Windows 11/10 must fit into one of the following brackets:

    1) Too young to remember a time before W10 and W11 (doesn’t know better)

    2) Wants to play the latest games on their PC above anything else (or deeply needs some software which already dropped W7 support)

    3) Doesn’t know too much about how computers work, worried that they’d be absolutely lost and in trouble without the “”latest security””

    4) Microsoft apologist that tries to justify that the latest “features” and “changes” are actually a good thing, that improve Windows

    5) Uses their computer to do a bare minimum of like 3 different things, browse web, check emails, etc, so really doesn’t fuss

    Obviously that doesn’t cover everyone, there’s also the category that:

    6) Actually liked W7 more than 10, and held out as long as possible before switching, begrudgingly uses 10 now

    Have I missed any group off this list?

    1. Heinz Strunk said on September 19, 2023 at 3:57 pm

      You have missed in this group just about any professional user that uses business software like CAD programs or ERP Programs which are 99% of all professional users from this list.

      Linux doesn’t help anyone who is not a linux kid and apple is just a fancy facebook machine.

  6. ilev said on August 24, 2023 at 7:34 pm

    Microsoft has removed KB5029351 update

    1. EP said on August 24, 2023 at 9:21 pm

      only from windows update though
      KB5029351 is still available from the ms update catalog site

  7. Anonymous said on August 24, 2023 at 11:05 pm

    1. This update is labaled as PREVIEW if it causes issues to unintelligent people, then they shouldn’t have allowed Preview updates ot install.

    2. I have installed it in a 11 years old computer, and no problems at all.

    3. Making a big drama over a bluescreen for an updated labeled as preview is ridiculous.

    This is probably another BS internet drama where people ran programs and scripts that modified the registry until they broke Windows, just for removing stuff that they weren’t even using just for the sake of it.
    Maybe people should stop playing geeks and actually either use Windows 10 or Windows 11, but don’t try to modify things just for the sake of it.

    Sometimes removing or stopping things (like defender is a perfect example) only need intelligence, not scripts or 3rd party programs that might mess with windows.

  8. john said on August 24, 2023 at 11:17 pm

    Windows 11 was a pointless release, it was just created because some of the Windows team wanted to boost sales with some sort of new and improved Windows 10. Instead, Microsoft cannot support one version well let alone two.

    1. John G. said on August 25, 2023 at 12:08 pm

      Windows 11 is the worst ugly shame by Microsoft ever. They should release with every new W11 version a complete free version of Starallback inside just to make this sh** OS functionally again.

  9. EP said on August 25, 2023 at 3:10 pm

    motherboard maker MSI has recently released a statement regarding the “unsupported processor” blue screen error for their boards using Intel 600/700 series chipsets & to avoid the KB5029351 Win11 update:

  10. EP said on August 29, 2023 at 7:32 pm

    check out the following recent articles:

    Neowin – Microsoft puts little blame on its Windows update after UNSUPPORTED PROCESSOR BSOD bug:

    BleepingComputer – Microsoft blames ‘unsupported processor’ blue screens on OEM vendors:

  11. Leonard Britvolli said on August 30, 2023 at 10:33 pm

    While there may be changes or updates to the Windows 10 Store for Business and Education in the future, it is premature to conclude that it will be discontinued based solely on rumors.

  12. sembrador said on September 5, 2023 at 9:32 pm

    My advice, I left win 15 years ago. Now I’m a happy linux user (linuxmint) but there is Centos, Fedora, Ubuntu depending on your needs.

  13. EP said on September 6, 2023 at 11:55 am

    motherboard maker MSI has recently released new BIOS/firmware updates for their Intel 600 & 700 series motherboards to fix the “UNSUPPORTED_PROCESSOR” problem (Sept. 6):


  14. Raphael Benzo said on September 24, 2023 at 9:52 pm

    I try to disable the Diagnostics Tracking Service (Connected Devices Platform User Services) but it wont let me disable it, any help will be greatly appreciated.
    Tank you for your help

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