Can UltraSentry wipe "empty" disk space?

[gmjewell]

Hello,

Is it possible for UltraSentry to wipe out what is supposedly "empty" space? There are several programs that don't allow deletion outside of their boundaries unless you want to hose things up.

That, and many files were deleted before the installation of UltraSentry.

How can you go over this space to make sure everything is wiped securely?


Thanks!

[TomTinsley]

UltraSentry can do it (somewhat). Actually it writes a file as big as it can and then deletes it. See "Wipe Unused Disk Space" in the help file Index.

[gmjewell]

Sorry for the delay. I was out of town. Thanks for the tip. It looks like it does what I need it to.

It would be nice, in a future version, if this were more prominently shown.

[koninger]

So, I understood, I can execute a profile, i.e. "total systen scrub", which also cleans unused space.

But, I can't take the risk to do all these things against C: (I will probably need the deleted data there) --- I just have to wipe a specific disk, say F:

Can I use UltraSentry for that task? How?

Maybe I can define an own, additional profile for that?

---> Here I finally, found the solution myself, thus I'm editing this post, hopefully giving other users a hint. When using the wizard, disabling everything it offers, after all the unwanted options, at the very last screen there is a small ticker box, which magically adds additional steps to the list. And here is the wipe-unused-space option. I saved the profile. Now I can run it as I need to -- just wipe specific free space, say on F:

[Mofi]

Here is the screenshot of the wizard window with the advanced features to wipe unused disk space.

Screenshot of the wizard dialog with the special cleaner operations.

wipe_unused_disk_space.png (36.23 KiB) Viewed 1776 times

Please note:
Don't use Clean File Slack Space on system drive where Windows is installed when Windows is running from this drive. That can harm your Windows installation. Why?

Files are stored on hard disk in clusters. One cluster can't contain data from two files. So every cluster has always only data of 1 file. Let's say you have an NTFS formatted drive with default cluster size of 4 KB (4096 bytes). A file with 7236 bytes needs therefore 2 clusters, one completely and the second one just partly. 956 bytes in the second cluster are unused and can contain therefore the data of a previous file.

The clean file slack space increases a file so that the last cluster of the file is completely used by the file. Then these bytes are secure overwritten with the level you select. Next UltraSentry decreases the file size to original size and restores last modification date.

While this procedure is no problem on data drives, it is a problem on Windows system drive because there are font files which are permanently in use. I could see on my Windows XP that UltraSentry increased also the font files in use and secure cleaned the unused bytes in last cluster of the font file. But because some of the font files are always in use by Windows, the decrease of the file size failed on those font files. So some font files have then a larger file size as before with 0xFF at end. Well, this is no problem. Those font files are still valid. So this is just a minor problem.

More problematic is the Windows system file protection mechanism. While UltraSentry cleans the file slack spaces, also system DLLs are increased in size temporarily. That triggers the Windows system file protection mechanism and Windows tries to restore the "modified" system DLLs from DLLCache or original installation location (CD, DVD). On my computer Windows XP asked me to insert the Windows XP CD. On the first 20 requests I simply canceled. But then it started annoying me and I inserted the Windows XP CD. That was a big failure. Windows XP now restored the protected system DLLs from the CD although the DLLs were already in the meantime restored to original content (= file size) by UltraSentry. The problem after letting Windows restoring the protected system files was now that some DLLs were the old versions from the CD while others were newer versions. The result was that some functions like Windows defragmentation or accessing the internet were not working anymore because of this mixture of old and new DLLs. I needed to restore my system drive from an image backup to get it fully working again.

That my Windows installation was harmed was not really the fault of UltraSentry, but nevertheless don't use Clean File Slack Space on the Windows system drive while running Windows from this drive.

Using Wipe Unused Disk Space on Windows system drive is no problem. I do that regularly and I have had never a problem.