Installation of Silverlight Fails with a generic error 1603 "Installation failed"


 Installation of Silverlight fails with a generic error 1603 "installation failed" after the installation progress shows 99% complete.


To find the root cause open the SilverlightMSI.log from the %temp% folder and it shows an error “Cannot create HKEY_LOCAL_MACHINE\SOFTWARE\MozillaPlugins\,version=1.0”.

This is because a MacAfee ‘Access Protection rule’ has been set on ‘Mozilla & FireFox files and settings’ which blocks Silverlight installer from creating the registry key. When we open the Access Protection log from the MacAfee console we can see entries like below

“Blocked by Access Protection rule %username% C:\WINDOWS\regedit.exe\REGISTRY\MACHINE\SOFTWARE\MozillaPlugins\\,version=1.0 Common Standard Protection: Protect Mozilla & FireFox files and settings Action blocked : Create”


 It is recommended to conatct MacAfee and Modify the ‘Access Protection rule’ on  ‘Mozilla & FireFox files and settings’, such that it allows Silverlight Installer to create the key. As a workaround we can disable ‘Access Protection’ from the MacAfee console, install Silverlight successfully and then enable ‘Access Protection’ back.

 Content by : Sarat Chandra

Comments (4)

  1. Chandana says:

    Thank you very much for posting this. It worked.

  2. Amit says:

    Another cause of the failure at 99% is the setup program not being to be able to do something as simple as stick a shortcut into your start menu.

    Your best bet is to analyse your SilverlightMSI.log file.

    My issue was reported as:

    MSI (s) (18:20) [18:59:38:579]: Product: Microsoft Silverlight — Error 1317. An error occurred while attempting to create the directory: C:ProgramDataMicrosoftWindowsStart MenuProgramsMicrosoft Silverlight

    Crazy thing is, this error message was hidden away 7/10th's of the way through the file. How clever Microsoft?

    Anyway, changing the permissions on my start menu fixed things and then it installed fine.

  3. richa says:

    Didn't solve…..

  4. Mark says:

    I'm using IE 11 and Chrome 35.0.1916.153 m.   Could not load Silverlight due to the "installation failed" 1603 error when installation hit 99%.  Looked at a bunch of different, more complex solutions.

    Went to the McAfee console, disabled on access scanner and access protection.  Then re-ran the installation.  BAM !!  Done.  

    Simple easy solution Sarat.  Thanks !!

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