How to fix Class not registered or 80040154 error

3.69 from 51 Reviews

"Class not registered" is one of the most annoying and frustrating error message I ever got because none of the video files can be played by Windows Media Player, Media Player Classic or other DirectShow player and common fix methods (Windows Media Player reinstallation/upgrade, codec reinstallation...) seems to fail.


Fortunately, the solution (in fact one of them because there are few different solutions) for this problem is very simple.

After some research I found that quartz.dll (a DirectX related DLL) wasn't registered correctly.

How to register it?

Click on Start > Run... > and type regsvr32 quartz.dll

Run dialog box



In the end, you should receive a message saying that your file was succesfully installed.
 

The file was succesfully installed



Note: Please, let us know if the solution suggested here wasn't helpful for you so we can try to complete this guide with other hints.

UN
Unnamed
on 15 December 2016
worked on a windows xp professional.
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Review by Unnamed
XI
xitiz
on 01 September 2016
i found class not registered in attendance management software. I format and installed a new software but again same problem is detected what can I do plz help me
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Review by xitiz
RM
Ryan Middleton
on 02 September 2015
Windows 10 error message:
"The module "quartz.dll" was loaded but the call to DllRegisterServer failed with error code 0x80070005.

For more information about this problem, search online using the error code as a search term."
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Review by Ryan Middleton
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