mht files no longer opening in Internet Explorer

I recently installed an application to view msg files outside of Outlook.  It worked fine, however today when I tried to open an mht file it tried to open in this application which filed to handle it.

I decided to uninstall this program (as I no longer needed it) expecting IE to handle .mht files again.  It didn't work.

Now IE opens, but instead of showing the file I get prompted to download it.  I have tried multiple files, all having the same issue.  These worked fine a couple of weeks ago.

I have already rebuilt the registry key [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\IE.AssocFile.MHT] copying values from a known good system (although using IE 10 not 11).  It didn't help.

I really want to avoid uninstalling and reinstalling, so your help would be appreciated.
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John EastonDirectorAsked:
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Your first three paragraphs are somewhat confusing (to me anyway).  It seems you have lost the association for .mht file.

Try a System Restore to the time before this started.

Control Panel|Default Programs|click "Associate a file type or protocol with a program "|scroll to .mht and make sure the Current Default association is IE.

Use the fix for mhtml here

See endeavor's last post here
It offers the code for a .reg file to fix this.

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John EastonDirectorAuthor Commented:
Sorry if my post was confusing.  I will try again below:

Essentially I installed a program which appears to have associated itself with .mht files.  I decided not to keep the program and uninstalled.  However, since doing so Internet Explorer no longer open the files (like it used to), instead IE opens and prompts me to Save the file.

I'm trying to avoid more drastic options of System Restores, or re-installing IE.  I can open the files if I use another browser like Chrome and manually open the file.  But I would like to try to fix the problem if I can.

Regarding the Default Association I have checked this and it is correctly associated with IE.
This was the second part of jcimmaron's post, and seems to go with exactly what  you are looking for ....
Import this into your registry, and it should fix the problem.

Windows Registry Editor Version 5.00

@="MHTML Document"
@="C:\\Program Files\\Internet Explorer\\iexplore.exe,-32554"
@="Open in S&ame Window"
@="\"C:\\Program Files\\Internet Explorer\\iexplore.exe\" -nohome"
@="\"C:\\Program Files\\Internet Explorer\\iexplore.exe\" %1"
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Have you tried the .reg file offered by endeavor per my post  http:#a40839766 ?

What do you find drastic about System Restore?  It does not involve uninstalling anything other than whatever you installed after the date of the Restore Point you choose.
jcimarron, that registry that I posted up there was a direct copy from your post, and I did give you credit for it, don't want you to think I'm trying to steal it :)
John EastonDirectorAuthor Commented:
I completely missed the links on jcimmaron's first post.  Sorry.  

I've just tried importing the .reg file and no difference.  I restarted IE -> does it need a full system restart to take effect?

Regarding System Restore I relented and tried that to.  But after 3 attempts (1 normal, 1 disabling AV software and 1 in safe mode) they all failed.
Have you run SFC /SCANNOW from an Admin Command Prompt?

If that does not help, I think you should consider a Repair Install.

It should not affect your personal data or installed programs.  But a back up first is always a good idea.
John EastonDirectorAuthor Commented:
SFC hasn't run successfully for a while.  Apparently it's a known issue in Windows 7 after a specific update.  Running the System Update Readiness Tool (which apparently does the same thing) doesn't find an errors.

I will look into a repair install.
John EastonDirectorAuthor Commented:
I uninstalled KB3022345, SFC still had errors.  The log led me to another known issue which has a fix available.  SFC now reports no errors.

However, system restore still fails.  How do I do a Repair install?  I don't think I have a Windows 7 disk - it was all preinstalled.  I don't even see a Windows Key sticker anywhere.
Can you contact the maker of the PC?  Normally the maker can supply you with both installation disk (perhaps for a small charge) and the Product Key.  
I can tell you how to make your own installation disk which has to be the exact version as the OS installed (for example, Win 7 SP1 or original, Home Premium or Ultimate) but you will have to have the Product Key.  There are apps that will find that, but E-E rules do not permit posting.
Also the disk will have to be full retail, not OEM.  OEM will only allow a full clean install.

Tell me what your situation is and we will proceed from there.

I gave you the instructions for a Repair Install earlier but you will need the Product Key.

What is the situation with ,mht files.  Did you try the .reg file for .mhtml in
John EastonDirectorAuthor Commented:
After a couple of evenings of trying to figure this out, I now appear to have found a solution.

I tried several things which probably made no difference, including uninstalling IE11 and reinstalling it (which gave me various headaches).

However, the solution appeared to lie in the Registry.  I got hold of another Win 7 computer where the files were working and compared keys.

In addition to the above Registry additions, in [HKEY_LOCAL_MACHINE\SOFTWARE\Classes\.mht] I had to change the "(Default)" value from "" to "mhtmlfile", and add a string "Content Type" with value "message/rfc822".  I did the same to the .mhtml key.

Suddenly IE now can open the file and display it correctly.
Thanks for telling us the fix.
John EastonDirectorAuthor Commented:
Thanks for all your help.
Glad to have helped.
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