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troubleshooting Question

The second unexpected EFS certificate in win7. Can't access new encrypted files

Avatar of BlueArgonaut
BlueArgonautFlag for United Kingdom of Great Britain and Northern Ireland asked on
EncryptionOS SecurityWindows 7
3 Comments1 Solution1341 ViewsLast Modified:
I use EFS encryption for several folders and their sub-folders (The new folders I created, My Documents, My Photos) in my folder C:\Users\MyLoginName. The "Application Data" or "App Data" are not encrypted.

I have EFS certificate for about 1 month with thumbnail beginning with: AA1A I backed up this EFS certificate including private key. When I checked the certificate in system it shows that certificate contains the private key.

Yesterday I suddenly got message that I should backup the EFS certificate. I didn't put attention to that because I understood that I already did backup. In the evening I found that I can't access some new files. I checked files encryption and I found that they have been encrypted with another certificate with thumbnail beginning with BB9B I checked certificates and I found the grant new certificate with thumbnail beginning with BB9B. That certificate has been created yesterday and in Certificates View shows that it CONTAINS private key as well. I tried to backup certificate BB9B and I couldn't save the private key! This option was not accessible.

The Recovery agent is without certificate. So I tried to add any of certificate I could find: AA1A or BB9B I got message "The certificate is not suitable for  Encrypting File System recovery".

I use Windows 7 64bits Ultimate. I didn't change password for any user on computer. The computer is on not on Active Directory it works in WORKGROUP. I haven't copy any file or folder between folders in C:\Users

Could you please help to answer:
1. Do you know what could cause that creation of the new certificate?
2. Is there any option to decrypt files with certificate BB9B?
3. Can I delete certificate BB9B?
4. What certificate can be used for Recovery agent?

Thanks a lot for your help. I appreciate it.
Avatar of Paranormastic
ParanormasticFlag of United States of America imageCryptographic Engineer

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