Is EFS file encryption useless? RRS feed

  • Question

  • I encrypted an Excel spreadsheet on my laptop using EFS.  I encrypted the file only.  Then I copied the file to a shared drive.  I remoted into my wife's PC, logged in using her credentials, and was able to open and read the Excel spreadsheet.

    Am I missing something?


    Sunday, March 11, 2018 2:46 AM

All replies

  • I have Windows 10 Pro.  If I use EFS to encrypt an Excel spreadsheet file on OneDrive, does that encryption remain in effect on OneDrive? (Not OneDrive for business) Meaning, if someone grabbed this file from OneDrive, would they need a password to open it?  I have some semi-sensitive spreadsheets I'd like to store on OneDrive, but not without encryption.

    I've read conflicting accounts.


    Saturday, March 10, 2018 3:43 AM
  • Hi,

    Based on your description, I will move your thread to Windows 10 security forum:


    The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.



    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    Monday, March 12, 2018 8:19 AM
  • This is not a normal behavior. Please check if the file you copied is still encrypted.

    You cannot use EFS on OneDrive. Once synced, the file is no longer encrypted. While OneDrive data are encrypted during transit and at rest, I would advise using Azure Information Protection of Excel file protection for further protection of your data.

    This posting is provided AS IS with no warranties or guarantees , and confers no rights.

    Ahmed MALEK

    My Website Link

    My Linkedin Profile

    My MVP Profile

    • Proposed as answer by Tony_Tao Tuesday, March 13, 2018 4:40 AM
    Tuesday, March 13, 2018 2:27 AM
  • Hi,

    We haven’t heard from you for a couple of days, have you solved the problem?  

    Please remember to mark the replies as answers if they help. If you have feedback for TechNet Subscriber Support, contact tnmff@microsoft.com.

    Monday, March 19, 2018 5:24 AM