Dear vmware-Support,
are there any known problems using Encrypting File System (EFS) with Windows Server 2016 on ESX 6.5?
We have been using EFS for years on Windows Server 2008 without any problems.
Four weeks ago, due to EOS of Server 2008, we moved everything (including the EFS-enabled production datastore = VMDK file) to another existing VM which is running Server 2016.
Right now I can't check the exact versions of the VMs involved but I believe we had v5 with 2008 and v8 with 2016 (but I might be wrong).
The symptom that I can see from within Server 2016 by using a low-level disk viewer is that the disk sectors that were previously holding the encrypted data of the affected files are now holding binary zeroes (0x00). However, the file system entries of the affected files are intact (file size, location of file content on disk, modified dates, attributes, etc.). When we try to open such a file, it is empty.
Some of the affected files were not changed for years (mostly JPG files) while some other affected files were created (or edited) after our migration to Server 2016 (mostly XLS files).
Additionally, I have found out that the provisioning type of the VMDK has changed in the process of remounting it - from "eager-zeroed" to "thin" and therefore the VMDK had 100GB less in size than before.
However, after we have dismounted and inflated the VMDK (now showing "eager-zeroed"), the problem did NOT disappear, i.e. we still have data loss sometimes when saving new files or editing existing files!
We are also working a lot with unencrypted documents on the same VMDK and did not have any problems with those files so far.
You can find a detailed explanation about the EFS encryption process here (direct link to book page) :
Windows Internals - David A. Solomon, Mark E. Russinovich, Alex Ionescu - Google Books
Best regards,
Christian