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What does the regsvr32 command do in the troubleshooting of Internet Explorer?

Posted on 2008-10-13
Medium Priority
Last Modified: 2013-12-08
Hi Everyone;

        From a previously closed post, I was given a link which illustrated the mechanics of how to use the regsvr32 command in repairing the browswer, Internet Explorer.  As I understand it, this command is used to register various core Internet Explorer libraries (urlmon.dll, shdocvw.dll, actxprxy.dll, oleaut32.dll, mshtml.dll, browseui.dll, and shell32.dll).  I am not sure if I have that interpretation right.  Assuming this technical interpretation is correct, what exactly does it mean when each of these library files of IE is being registered?  Does that mean each one of these core files are being returned to their default condition?  Additionally, why are these file referred to as "core" files?  I assume this means these dll files are crucial to the basic functionality of IE, such as opening HTML pages, loading plug ins, etc.

         In closing, any followup to my interpretations of the technical usefulness of the regsvr32 command will be appreciated.  

         Thank you

Question by:GMartin
LVL 15

Assisted Solution

hewittg earned 200 total points
ID: 22707859

Assisted Solution

bigdaddyz99 earned 400 total points
ID: 22707949
Regsvr32 basically just registers a dll with windows so that when a program tries to load the dll, windows can find it.    This allows programs to use a dll without knowing anything about its physical location.  It does not make any changes at all to the dll itslef.

The core dll's contain a lot of the functionality of the browser most of which can also be used by other programs which load the DLLs and use the features just like the browser does.

Accepted Solution

Shedding earned 800 total points
ID: 22707985
I will tell you exactly what you are doing when you are using regsvr32.  Basically, every program on any operating system needs to be converted from a set of instructions produced by a programming language (like C, Pascal , fortran, Java, etc) to an executable.  The computer needs to compile the written instructions into something the computer can interpret.  In windows you have an executable file ending with the extension .exe.  For example, to load internet explorer.. go to start, then run and type "iexplore.exe" and you will notice internet explorer runs and loads.  Sometimes, an executable (a program) needs to make a call to the operating system for any reason (disk access, load a standard window, etc) - These other programs are also executables but they are in the form of .DLL which only windows can run as a call.    So lets say you want to install a game.. you run a setup.exe within the CDROM and all of the sudden you see the install shield wizard.  Have you noticed how every time you install something it looks exactly the same (install shield wizard)?  that is because the executable that you ran (setup.exe) is making a .dll call to the operating system to use the install shield dll.  Basically anything you do in windows that is repetitive will have some sort of DLL attached to it.  Hopefully this helps in understanding a bit more how DLL's work.  One last thing, when your internet explorer wasn't working.. IE was making calls to a DLL but did not know what path they where they existed in.. when you registered the DLL files with regsvr32, you told windows where those files were located in case a program made a call to them.  

LVL 97

Assisted Solution

war1 earned 600 total points
ID: 22708381
Hello George,

I was in the post where another expert propose registering the dll files.  Sometimes when another program is installed, and it uses the same dll files as Internet Explorer.  So the dll file becomes registered to the other program and unregistered to IE.  Thus IE does not function properly.  Registering the file fixes the problem.

Registering the dll files fixes some IE problem, but does not fix all IE problems. It is not the cure all for all IE errors.  I mainly suggest the fix when links in IE or Outlook does not open to IE webpage.  Also, there is a script put together by an Microsoft MVP to run the registration automatically, which is shown below.

You may need to register some dll files
1. Quit all programs that are running.
2. Click Start, and then click Run.
3. Type regsvr32 urlmon.dll, and then click OK.
4. When you receive the "DllRegisterServer in urlmon.dll succeeded" message, click OK.

If this does not resolve the problem, repeat steps 2 through 4 for each of the following files (in step 3, replace Urlmon.dll with each of the file names below):


Run this script if using IE6

Hope this helps!

Author Comment

ID: 22792956
Hi Everyone;

        Thanks so much for the shared input.  Using everyone's feedback in addition to the link supplied, I certainly have a much better understanding and appreciation for the Regsvr32 command.  Without a doubt, looking at the behind the scenes things which happen between the .exe file, the operating system, and the called .dll certainly help tie all of this together.

        Many thanks again.


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