Article ID: 127655, created on Dec 1, 2015, last review on Aug 21, 2016

  • Applies to:
  • Plesk 12.5 for Windows


  • Site is loaded without .css files.


  • Attempt to open IIS > Sites > > MIME Types for domain fails with error:

    MIME Types
    There was an error while performing this operation.
    Filename: \\?\C:\Windows\system32\inetsrv\config\applicationHost.config
    Line number: 11979
    Error: Cannot add duplicate collection entry of type 'mimeMap' with unique key attribute 'fileExtension' set to '.woff'


Already existing records in C:\Windows\System32\inetsrv\config\applicationHost.config or .css extension is not allowed in custom C:\inetpub\vhosts\\httpdocs\Web.config file.


In case of custom C:\inetpub\vhosts\\httpdocs\Web.config, review its code and make sure .css extension is allowed.

Otherwise, remove the site cache and reconfigure domain:

"%plesk_bin%\websrvmng" --remove-sites-cache

"%plesk_cli%\repair" --reconfigure-web-site -web-site-name

If it does not help:

  1. Back up the current IIS configuration using the following command in cmd.exe:

    %windir%\system32\inetsrv\appcmd.exe add backup "My Backup Name"
  2. Open %windir%\system32\inetsrv\config\applicationHost.config file in text editor and remove the line specified in the symptoms (Line number: 11979):

    <mimeMap fileExtension=".woff" mimeType="font/x-woff" />
  3. Reconfigure the domain:

    "%plesk_cli%\repair" --reconfigure-web-site -web-site-name

Search Words

with unique key attribute

Cannot add duplicate collection entry of type

CSS are not displayed

Site is loading without .css files


css files does not load




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