We have an old Windows 7 machine that needs to be returned to a client and as such, I need to make sure the free space has been erased. There is single deleted file that is never overwritten. It is a large (600MB) zip file of email messages.
I have used CCleaner, Glary, Eraser, Privacy Eraser and FreeSpaceWipe; erasing cluster tips, free space, MFT free space and recoverable MFT file names. 0s, 1s, random; single pass and 3 pass DoD. This particular file (Thunderbird.zip) is ALWAYS LEFT. Nothing else is recoverable (Recuva). chkdsk finds no disk errors.
I've tried recovering the file (it unzips successfully) and then deleted it to no avail, and I then recovered it again and shredded it in the recycle bin. No joy. The file can always be recovered.
It's driving me nuts! Has anyone experienced something like this?
Update: Thanks to all for your help. The undeletable file is created by Recuva. The file contains deleted but not removed emails from Thunderbird (or Outlook). There’s no way to disable this ‘feature’.
As a new user of the program, I eventually noticed that in the Recuva output I could right click on the file and tell Recuva to securely delete it, at which you point you receive the error message:
“unable to overwrite special file type.”
Searching on this string led me to more information.
I reduced the size of the file from 600MB to 200k by using a Thunderbird add-on called Xpunge to compact all the email folders, but there were still several deleted emails remaining and the zip file was still created. To make sure that this was the answer, I zipped the Thunderbird profile folder and deleted the profile folder. The Thunderbird emails.zip file was no longer created.
For my purposes Thunderbird will be deleted before handing over the machine, so I’ll be okay. Thank you all so much for your willingness to help and your great suggestions. They kept me going when I was about to surrender!
