Microsoft's Really Hidden Files: A New Look At Forensics



I will not be liable for any damage or lost information, whether due to reader's error, or any other reason.



There are folders on your computer that Microsoft has tried hard to keep secret. Within these folders you will find two major things: Microsoft Internet Explorer has not been clearing your browsing history after you have instructed it to do so, and Microsoft's Outlook Express has not been deleting your e-mail correspondence after you've erased them from your Deleted Items bin. (This also includes all incoming and outgoing file attachments.) And believe me, that's not even the half of it. When I say these files are hidden well, I really mean it. If you don't have any knowledge of DOS then don't plan on finding these files on your own. I say this because these files/folders won't be displayed in Windows Explorer at all -- only DOS. (Even after you have enabled Windows Explorer to "show all files.") And to top it off, the only way to find them in DOS is if you knew the exact location of them. Basically, what I'm saying is if you didn't know the files existed then the chances of you running across them is slim to slimmer. It's interesting to note that Microsoft does not explain this behavior adequately at all. Just try searching on



I know there are some people out there that are already aware of some of the things I mention. I also know that most people are not. The purpose of this tutorial is teach people what is really going on with Microsoft's products and how to take control of their privacy again. This tutorial was written by me, so if you see a mistake somewhere then it is my mistake, and I apologize.


Thanks for reading.




1.1) Ancronyms



3.1) If You Have Ever Used Microsoft Internet Explorer

3.2) Clearing Your Registry

3.3) Slack files

3.4) Keeping Microsoft's Products






8.1) Removing Find Fast


9.1) Recommended reading




Coming in version 3.0:


- Related Windows Tricks.

- Looking back on the NSA-Key.

- Researching the [Microsoft Update] button.

- Why the temp folders aren't intended to be temporary at all.

- What's with Outlook Express's .dbx database files?

- Win2K support.



I) A "really hidden" file/folder is one that cannot be seen in Windows Explorer after enabling it to "show all files," and cannot be seen in MS-DOS after receiving a proper directory listing from root.

a) There is at least one loophole to enable Windows Explorer to see them.

b) There is at least one loophole to enable MS-DOS to see them.

II) Distinguishes "really hidden" file/folders from just plain +h[idden] ones, such as your "MSDOS.SYS" or "Sysbckup" folder.

III) Distinguishes from certain "other" intended hidden files, such as a file with a name with high ascii characters (eg, "Yo").

(Interesting to note that Microsoft has disabled the "Find: Files or Folders" from searching through one of these folders.)



DOS = Disk Operating System aka MS-DOS

MSIE = Microsoft Internet Explorer

TIF = Temporary Internet Files (folder)

HD = Hard Drive

OS = Operating System

FYI = For Your Information



No. Enabling Windows Explorer to "show all files" does not show the files in mention. No. DOS does not list the files after receiving a proper directory listing from root. And yes. Microsoft intentionally disabled the "Find" utility from searching through one of the folders. Oh, but that's not all. Just from one of these files I would be able to tell you which web sites you previously visited, what types of things you search for in search engines, and probably gather your ethnicity, religion, and sexual preference. Needless to say one can build quite a profile on you from these files. It has the potential to expose and humiliate -- putting your marriage, friendship, and corporation at risk. Here's one good example of the forensic capabilities.. "I've been reading your article as I have a problem with an employee of mine. He has been using the works pc for the internet and using it to chat and look at porn sites. He was then deleting the cookies and history in order to cover his tracks. A friend of mine pointed me in the direction of this site and your article. I have found it to be incredibly useful,..." --Concerned Boss, 8/24/01

One more thing. They contain your browsing history at ALL times. Even after you have instructed Microsoft Internet Explorer to clear your history/cache. And so the saying goes, "seeing is believing..." To see for yourself simply do as you would normally do to clear your browsing history. Go to Internet Options under your Control Panel. Click on the [Clear History] and [Delete Files] buttons. (Make sure to include all offline content.)

So, has your browsing history been cleared? One would think so... Skipping the to chase here. These are the names and locations of the "really hidden files:"



If you have upgraded MSIE several times, they might have alternative names of mm256.dat and mm2048.dat, and may also be located here:



Not to mention the other alternative locations under:


c:\windows\application data\...

c:\windows\local settings\...



FYI, there are a couple other index.dat files that get hidden as well, but they are seemingly not very important.



Step by step information on how to erase these files as soon as possible. This section is recommended for the non-savvy. Further explanation can be found in Section 4.0. Please note that following these next steps will erase all your internet cache and cookies files. If you use the offline content feature with MSIE, it will remove this as well. It will not erase your bookmarks.



1) Shut your computer down, and turn it back on.

2) While your computer is booting keep pressing the [F8] key until you are given an option screen.

3) Choose "Command Prompt Only." This will take you to real DOS mode. ME users must use a bootdisk to get into real DOS mode.

4) When your computer is done booting, you will have a C:\> followed by a blinking cursor. Type in this hitting enter after each line (sans parenthesis):

C:\WINDOWS\SMARTDRV (Loads smartdrive to speed things up.)


DELTREE/Y TEMP (This line removes temporary files.)


DELTREE/Y COOKIES (This line removes cookies.)

DELTREE/Y TEMP (This removes temporary files.)

DELTREE/Y HISTORY (This line removes your browsing history.)

DELTREE/Y TEMPOR~1 (This line removes your internet cache.)

(If this last line doesn't work then type this:)



(If this doesn't work then type this:)




(If this still does not work, and you are sure you are using MSIE 5.x, then feel free to e-mail me. If you have profiles turned on, then it is likely located under \windows\profiles\%user%\, while older versions of MSIE keep them under \windows\content\.)

This last one will take a ridiculous amount of time to process. The reason it takes so incredibly long is because there is a TON of useless cache stored on your HD.

5) Immediately stop using Microsoft Internet Explorer and go with any of the alternative browsers out there. Netscape 4.7x from, mozilla from, or opera from FYI, Windows re-creates the index.dat files automatically when you reboot your machine so don't be surprised when you see them again. They should at least be cleared of your browsing history.



It was once believed that the registry is the central database of Windows that stores and maintains the OS configuration information. Well, this is wrong. Apparently it also maintains a bunch of other information that has absolutely nothing to do with the configuration. I won't get into the other stuff but for one, your Typed URLs are stored in the registry.


HKEY_USERS/Default/Software/Microsoft/Internet Explorer/TypedURLs/

HKEY_CURRENT_USER/Software/Microsoft/Internet Explorer/TypedURLs/


These "Typed URLs" come from MSIE's autocomplete feature. It records all URLs that you've typed in manually in order to save you some time filling out the address field. By typing "ama" the autocomplete feature might bring up "" for you. Although, I find it annoying, some people prefer this feature. One thing is for sure however -- it's an obvious privacy risk. You wouldn't want a guest to type "ama" and have it autocomplete to

"" now would you?

You can clear your Typed URLs out of your registry by doing going to your Control Panel > Internet Options > Content > [AutoComplete] > and finally [Clear Forms]. If you feel the AutoComplete feature is a privacy risk, then uncheck the appropriate boxes here. FYI, this section has nothing to do with "really hidden files." It was added so people can completely clear their browsing history before having to ditch Microsoft Internet Explorer.



As you may already know, deleting files only deletes the references to them. They are in fact still sitting there on your HD and can still be recovered by a very motivated person.

- BCWipe is a nice program that will clear these files. (

- For you DOS buffs, there's a freeware file wiper on that I use. (

- If you are using PGP then there is a "Freespace Wipe" option under PGPtools.

- The newer versions of Norton Utilities has a nice filewiping utility.

- You might want to check out Evidence Eliminator's 30 day trial. This is probably the best program as far as your privacy goes. (



If your work environment forces you to use Microsoft Internet Explorer then I strongly recommend that you talk your boss into checking out one of these programs:


- PurgeIE (

- Cache and Cookie Cleaner for IE (

- Anonymizer Window Washer (



These programs automate the process for you, and is far better then having to ad 'deltree/y' lines to your autoexec. AND if your work environment forces you to use Outlook or Outlook Express then

you should get in the habit of compacting your mailboxes. You can do this by going to File > Folder > Compact All if you have Outlook Express.


Tools > Options > Other tab > [Auto Archive] if you have Outlook. Make sure to set things up here.



This next section is intended for the savvy user.

The most important files to be paying attention to are your "index.dat" files. These are database files that reference your history, cache and cookies. The first thing you should know is that the index.dat files is that they don't exist in less you know they do. They second thing you should know about them is that some will *not* get cleared after deleting your history and cache. The result: A log of your browsing history hidden away on your computer after you thought you cleared it.

To view these files, follow these steps:

In MSIE 5.x, you can skip this first step by opening MSIE and going to Tools > Internet Options > [Settings] > [View Files]. Now write down the names of your alphanumeric folders on a piece of paper. If you can't see any alphanumeric folders then start with step 1 here:

1) First, drop to a DOS box and type this at prompt (in all lower-case) to bring up Windows Explorer under the correct directory...

c:\windows\explorer /e,c:\windows\tempor~1\content.ie5\

You see all those alphanumeric names listed under "content.ie5?" (left-hand side.) That's Microsoft's idea of making this project as hard as possible. Actually, these are your alphanumeric folders that was created to keep your cache. Write these names down on a piece of paper. (They should look something like this: 6YQ2GSWF, QRM7KL3F, U7YHQKI4, 7YMZ516U, etc...) If you click on any of the alphanumeric folders then nothing will be displayed. Not because there aren't any files here, but because Windows Explorer has lied to you. If you want to view the contents of these alphanumeric folders you will have to do so in DOS. (Actually, this is not always true. *Sometimes* Windows Explorer will display the contents of the alphanumeric folders but mostly it won't. I can't explain this.)

2) Then you must restart in MS-DOS mode. (Start > Shutdown > Restart in MS-DOS mode. ME users use a bootdisk.)

Note that you must restart to DOS because windows has locked down some of the files and they can only be accessed in real DOS mode.

3) Type this in at prompt:


CD %alphanumeric%

(replace the "%alphanumeric%" with the first name that you just wrote down)

4) DIR/P

The cache files you are now looking at are directly responsible for the mysterious erosion of HD space you may have been noticing. One thing particularly interesting is the ability to view some your old e-mail if you happen to have a hotmail account. (Oddly, I've only been able to retrieve hotmail e-mail, and not e-mail from my other web-based e-mail accounts. Send me your experiences with this.) To see them for yourself you must first copy them into another directory and THEN open them with your browser. Don't ask

me why this works.

A note about these files: These are your cache files that help speed up your internet browsing. It is quite normal to use this cache system, as every major browser does. On the other hand. It isn't normal for some cache files to be left behind after you have instructed your browser to erase it.

5) Type this in:



You will be brought to a blue screen with a bunch of binary.

6) Press and hold the [Page Down] button until you start seeing lists of URLs. These are all the sites that you've ever visited as well as a brief description of each. You'll notice it records everything you've searched for in a search engine in plain text, in addition to the URL.

7) When you get done searching around you can go to File > Exit. If you don't have mouse support in DOS then use the [ALT] and [Arrow] keys.

8) Next you'll probably want to erase these files by typing this:




(replace "cd\windows" with the location of your TIF folder if different.) This will take a seriously long time to process. Even with smartdrive loaded.

9) Then check out the contents of your History folder by typing this:



You will be brought to a blue screen with more binary.

10) Press and hold the [Page Down] button until you start seeing lists of URLS again. This is another database of the sites you've visited.

11) And if you're still with me type this:


12) If you see any mmXXXX.dat files here then check them out (and delete them.) Then...




More URLs from your internet history. Note, there are probably other mshist~x folders here so you can repeat these steps for every occurence if you please.

13) By now you'll probably want to type in this:





How does Microsoft make these folders/files invisible to DOS?

The only thing Microsoft had to do to make the folders/files invisible to a directory listing is to set them +s[ystem]. That's it. As soon as the dir/s command hits a system folder, it renders the command useless (unlike normal folders.) A more detailed explanation is given in Section 6.

So how does Microsoft make these folders/files invisible to Windows Explorer?

The "desktop.ini" is a standard text file that can be added to any folder to customize certain aspects of the folder's behavior. In these cases, Microsoft utilized the desktop.ini file to make these files invisible. Invisible to Windows Explorer and even to the "Find: Files or Folders" utility (so you wouldn't be able to perform searches in these folders!) All that Microsoft had to do was create a desktop.ini file with certain CLSID tags and the folders would disappear like magic.

To show you exactly what's going on:

Found in the c:\windows\temporary internet files\desktop.ini and the c:\windows\temporary internet files\content.ie5\desktop.ini contains this text:




Found in the c:\windows\history\desktop.ini and the c:\windows\history\history.ie5\desktop.ini contains this text:





The UICLSID line cloaks the folder in Windows Explorer. The CLSID line disables the "Find" utility from searching through the folder. (Additionally, it gives a folder the appearance of the "History" folder.) To see for yourself, you can simply erase the desktop.ini files. You'll see that it will instantly give Windows Explorer proper viewing functionality again, and the "Find" utility proper searching capabilities again. Problem solved right? Actually, no. As it turns out, the desktop.ini files get reconstructed every single time you restart your computer. Nice one, Slick. Luckily there is a loophole which will keep Windows from hiding these folders. You can manually edit the desktop.ini's and remove everything except for the "[.ShellClassInfo]" line. This will trick windows into thinking they have still covered their tracks, and wininet won't think to reconstruct them. I can't stress how ridiculous it is that Windows actually makes sure the files are hidden on every single boot. No other files or folders get this kind of special treatment. So what's the agenda here?

6.0. +S MEANS [S]ECRET NOT [S]YSTEM Executing the "dir/a/s" command from root *should* be the correct command to display all files in all subdirectories in DOS. However, doing so will not display the index.dat files. This is because when DOS tries to get a list of the subdirectories of any +s[ystem] directory it hits a brick wall. No files or folders will be listed within any system directory. Not only does this defeat the whole purpose of the "/s" switch in the first place, but I'd say it looks like Microsoft took extra precautions to keep people from finding the files. Remember. The only thing you need to do to obscure a file in DOS is to mark the parent directory +s[ystem].

I was told by a few people that this was due to a very old DOS bug that dates back many years. Fine. I can accept that. A bug it is.

But, would you consider your Temporary Internet Files to be "system files?" It would seem that your TIF folder appears to be marked +s[ystem] for no good reason at all. Just because. Same with your history folder. You may not agree, but I tend to think that Microsoft marked the folders as +s[ystem] solely to hide any directory recursal from DOS.

In case you didn't understand, here's a small experiment that will show you what I mean...

Since the content.ie5 and history.ie5 subfolders are both located within a +s[ystem] folder, we will run the experiment with them. The proper command to locate them *should* be this:


DIR *.IE5 /as/s

The problem is that you will receive a "No files found" error message. Since we already know there is a content.ie5 subfolder located here, why is it giving me the "no files found" message?

But there is a way to get around this brick wall. That is, once you are inside the system directory, then it no longer has an effect on the dir listings. For example, if you enter the system folder first, and THEN try to find any +s[ystem] directories you can see them just fine:


DIR *.IE5 /as/s

1 folder(s) found.

Now you will get a "1 folder(s) found." message. (But only after you knew the exact location.)

In other words, if you didn't know the files existed then finding them would be almost impossible.

And, by the way. To see the "bug" in progress...


DIR *.IE5 /a/s

It will echo "no files found."

Now, just take away the system attributes from the parent directory...



And retry the test...


DIR *.IE5 /a/s

It will echo "1 folder(s) found."



Would you think twice about what you said if you knew it was being recorded?

E-mail correspondence leaves a permanent record of everything you've said -- even after you've told Outlook Express to erase it. You are given a false sense of security sense you've erased it twice, so surely it must be gone. The first time Outlook simply moves it to your "Deleted Items" folder. The second time you erase it Outlook simply "pretends" it is gone. The truth is your messages are still being retained in the database files on your HD. (As with your e-mail attachments.)

For earlier versions of Outlook Express, they will be located in either of the following folder:

c:\program files\internet mail and news\%user%\mail\*.mbx

c:\windows\application data\microsoft\outlook\mail\*.mbx

At this point you have two choices.

a) Get in the habit of compacting your folders all the time.

b) Backup, print-out, or import the data into another e-mail client such as Eudora and then delete the mbx files (and thus all your e-mail correspondence) by typing this:


deltree/y mail



deltree/y mail

*Typing in the above commands will kill all your e-mail correspondence. Do not follow those steps in less you have already exported your e-mail and address book!

If you have a newer version of Outlook or Outlook Express the databases are located elsewhere. Look for .dbx and .pst file extensions. These databases are five times as creepy, and I strongly recommend you take at the files. Just from my outbox.dbx file I was able to view some of my old browsing history, bring up previously-visited websites in html format, and even read ancient e-mail from my Eudora client (read: EUDORA). Again, don't take my word for it. See for yourself and THEN tell me what you think Slick Willy is up to here.



Have you ever wondered what that "Find Fast" program was under your control panel? Here's a hint: It has absolutely nothing to do with the "Find" utility located under the [Start] menu. Just to clear up any confusion before going on, Oblivion adequately explains Find Fast here: "In any version of Word after 95, choose File Open and you'll get the Office App Open dialog. Instead of just a space for the file name, there are text boxes for file name, files of type, text or property & last modified. These are search criteria you can use to find one or more files. There is also an "Advanced" button that opens a dedicated search dialog with more options. When you use either of these dialogs to perform a search, that search process uses the indexes built by Find Fast." --Oblivion

But what would you say if I told you that Find Fast was scanning every single file on your hard drive? Did you know that in Office 95, the Find Fast Indexer had an "exclusion list" comprised of .exe, .swp, .dll and other extensions, but the feature was eliminated? If you were a programmer would you program Find Fast to index every single file, or just the ones with Office extensions? FYI, If you have ever had problems with scandisk or defrag restarting due to disk writes, it is because Find Fast was indexing your hard drive in the background. It loads every time you start your computer up. Now here is a good example of the lengths Microsoft has gone through to keep people from finding out Find Fast is constantly scanning and indexing their hard drives. (Always good to have an alibi.) Here's a snippet taken from

"When you specify the type of documents to index in the Create Index dialog box, Find Fast includes the document types that are listed in the following table.

Document type File name extension MS Office and Web Documents All the Microsoft Excel, Microsoft PowerPoint, Microsoft Project, and Microsoft Word document types listed in this table. Microsoft Binder (.odb, .obt) and Microsoft Access (.mdb) files. Note that in .mdb files, only document properties are indexed. Word documents .doc (document), .dot (template), .ht* (Hypertext Markup

Language document), .txt (text file), .rtf (Rich Text Format) files, Excel workbooks .xl* files PowerPoint .ppt (presentation), .pot (template), .pps (auto-running presentation) files Microsoft Project files .mpp, .mpw, .mpt, .mpx, .mpd files All files *.* files"

Did you get that last part? "All files?" Find Fast indexes Office Documents, Web documents, Word Documents, Power Point files, Project files, and (oh I forgot) EVERY SINGLE other file on your computer. Actually, the good news is that this isn't necessarily true. In another statement Microsoft claims that if Find Fast deems the file "unreadable" then the file will not be included in the index. For example, your probably wouldn't get indexed because it doesn't have a lot of plain text -- mostly binary. But, back to the bad news. Every single file that has legible text is going to be included in the Find Fast database. Do you understand the implication here? ALL TEXT SAVED TO YOUR HARD DRIVE IS INDEXED. The forensic capabilities are enormous, folks. Don't forget "all text" also means previously-visited webpages from your cache. See for yourself...

1) Open up a DOS window and type...

2) CD\

3) DIR FF*.* /AH (This will bring up a list of the find fast databases.)

4) EDIT /75 %ff% (insert %ff% with any of the names that were listed.) Notice the incredible amount of disk accesses to your cache and history folders? Why do we need two indexes?



You can remove Find Fast using your Office CD, but I recommend you do it manually...

1) Reboot your computer in MS-DOS Mode.

2) Delete the findfast.cpl file from c:\windows\system\.

3) Delete the shortcut (.lnk) under


4) Delete the findfast.exe file from c:\progra~1\micros~1\office\.

5) Important to delete the find fast databases (c:\ff*.*).

6) You can also safely delete

FFNT.exe, FFSetup.dll, FFService.dll, and FFast_bb.dll if you have them. Feel free to check out the ffastlog.txt (which is the Find Fast error log).

It's a +h[idden] file under c:\windows\system\.


Thanks for reading

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Last Update: Thursday, June 24, 2003 | © 2002-2003 Kay Nix  ·  K-SeCuRiTy Timisoara, Romania