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Firefox 18 does not start after update - missing msdmo.dll

Posted

Following the latest update, each time i try to start FF I get 4 consecutive system error windows:

By 3 times the message is "impossible to start the program since msdmo.dll is missing on your computer. Try to reinstall the program to fix the problem". These messages appears in French (I have French language Windows and FF installed). Then the fourth error message is : "couldn't load XPCOM". (this time the message is in English).

msdmo.dll is present in my \windows\system32 folder, while XPCOM.dll is present in the FF folder.

I tried to download and reinstal FF, I even tried the beta version 19. I followed the clean install procedure found on thE Mozilla website with no success. I ran tree malware scanners and found nothing. I'm using MS Security Essentials and the built-in firewall of windows 7.

Internet Explorer is functioning well, as well as a portable version of Google Chrome with has the same addons as my FF setup : Adblock, Lastpass, and Xmarks.

I really don't see what else i can do?

Additional System Details

Application

  • User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.17 (KHTML, like Gecko) Chrome/24.0.1312.52 Safari/537.17

More Information

It's not possible to paste info as FF is not running.

cor-el
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10762 solutions 96861 answers

Helpful Reply

Try a clean reinstall and delete the Firefox program folder before reinstalling a fresh copy of Firefox.

  • (32 bit Windows) C:\Program Files\Mozilla Firefox\
  • (64 bit Windows) C:\Program Files (x86)\Mozilla Firefox\

Download a fresh Firefox copy and save the file to the desktop.

Uninstall your current Firefox version, if possible, to cleanup the Windows registry and settings in security software.

  • Do NOT remove personal data when you uninstall your current Firefox version, because all profile folders will be removed and you will also lose your personal data like bookmarks and passwords from profiles of other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

Your bookmarks and other profile data are stored in the Firefox Profile Folder and won't be affected by an uninstall and (re)install, but make sure that "remove personal data" is NOT selected when you uninstall Firefox.

If you keep having problems then also create a new profile.


Helpful Reply

Thank you for the response, I had already done all that prior to posting; did not fix the problem

cor-el
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10762 solutions 96861 answers

You can use the System File Checker to check if files are missing or corrupted.

Open a cmd.exe window as Administrator:

Start, click Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

After the cmd.exe prompt, type: sfc.exe /scannow

Question owner

I ran the File Checker, although some errors were found, nothing in relation with msdmo or xpcom. The problem is still there.

Question owner

Using Process Monitor tool from SysInternal Suite, i could eventually find that Firefox is seeking several folders in order to find msdmo.dll, but strangely, not windows/system32. Maybe a path is wrongly defined? anyway i copied msdmo.dll from system32 to the firefox folder, and it fixed these errors. I guess this is only a temporary fix as the next update of firefox, assuming that someday it will work again, will wipe the content of the folder. I would prefer find the way to instruct firefox to look in the proper place.

Still no clue for the XPCOM error.

cor-el
  • Top 10 Contributor
  • Moderator
10762 solutions 96861 answers

Make sure that the msdmo.dll is registered properly (REGSVR32 msdmo.dll).

Question owner

Using regsvr32 results in an error : msdmo.dll was loaded, but the DllRegisterServer entry point was not found.