I create a new Word document in 'Office Open XML' format (docx). I then encrypt it using EFS and add several other users to access the file.

Now I open the document and edit it, after saving it, the file is still encrypted but the additional users are gone! This means I have to remember which users I gave access to originally and add them again every time I edit a document.

If I do the same with a different file type, say *.txt, the additional users are kept after editing.

I assume this happens because the new Office documents are zip files that are unpacked and then re-created rather than just opened and closed. Word is smart enough to apply EFS encryption again, but only for the current user.

Does anybody know a way around this?

We are using Office 2010 on Windows 7 with AD based EFS.


According to Microsoft Support, this is a bug. When using Windows Encrypted File System with modern Office documents and multiple users (certificates) the additional user-certificates are lost after the file has been edited.

The problem still exists on Windows 8 with Office 2013

It may be a conceptual problem and I don't know whether it will or can be fixed.

  • Microsoft Server 2012R2 and Microsoft Office 2013. Issue still exist. but it's not a problem of modern xml type file formats. when I edit ODT file with MS Excel certificates of other users disappear as well. But when I edit .xslx with LibreOffice Calc certificates stays. – Jack Rider Feb 20 '18 at 14:39

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