How to reset .msi file associations with the right Microsoft application?

Jean Cadet August 5, 2010

Using Windows 7, my .msi files keep being opened by the Notepad instead of installing programs.

Under “Default Programs”, after I clicked ‘Associate a file type or protocol with a specific program’ it shows that the .msi extension for MSI files is associated with the notepad. Ditto the .msp extension for MSP files is associated with the notepad. I also noticed there that many extensions like .mydocs, .pcb, .pptmhtml are associated with UNKOWN application.

How can I at least have the MSI and MSP files have the correct associated Microsoft programs? Does it require going through registry to fix it?

  1. Best Registry Cleaner
    November 28, 2010 at 2:53 pm

    Ditto the .msp extension for MSP files is associated with the notepad.

  2. dRC
    November 10, 2010 at 3:52 pm

    I don't think HOW to change a file association is the question here people... The question is WHAT Microsoft programs opens MSI files!?! I have the same problem! Changing the association is easy, but to WHAT!? What program is the default program...?

  3. Aibek
    August 13, 2010 at 11:54 am


    Did you manage to fix the issue using the tips above? Let us know.


  4. Steve Campbell
    August 6, 2010 at 4:54 pm

    Whenever I want to do something like this I just right click the file, select Open With... and choose the program I want to open that file. If you tick the box that says Make Default it will open with that program every time.

  5. Tina
    August 6, 2010 at 6:02 am


    a similar question was asked previously, please check the answers here: //

    Basically, you can manually change the file associations and assign the correct programs to the respective file extensions.