I want to customize default Seattle.master page in sharepoint 2013.

As per my knowledgewe there are two files seattle.master & seattle.html, and we can able to make changes in any file.

But i want to know, from above, which one is recommended way or good practice to customize master page?

  • 2
    whatever you do, avoid making changes to ootb files. create your own master page, call it what you want to call it, and then customize away. other than that, learn what design manager is and what is the difference between editing the .html or the .master. Oct 4, 2017 at 8:18

3 Answers 3


Best practice to customize the MasterPage.

  • First of all take backup of Seatle.master.
  • Create new MasterPage from existing one
  • Set the new MasterPage as default MastePage
  • When you copy Seatle.master, it will produce 2 files. First will be *.master and second will be *.html
  • Don't try to update the *.master file. Always open the *.html file and customize the HTML design layout.
  • I hope you are using SPD to customize the MasterPage, if it is correct, then SPD will not allow to modify the *.master file.

Important Note:

Do not delete any comments from *.html file. If you do so, it will generate an error in MasterPage.

Find the default classes and apply your custom design there.

If you need more information, let me know.


If you enable publishing feature, you can’t edit .master directly, you should edit .html only suggested by Aakash Morya.

If you create a site collection(eg:Team Site) and don’t enable publishing feature, you could copy default .master page and do customization.


Best Practice to create a New Theme (Template) for your project, and apply your new Template as a Master Page.

To apply your New Created Theme (Template) Follow Below Steps:

  1. : Go to Your Site Setting
  2. : Click On Design Manager inside the Look And Feel Section.
  3. : Click on Edit Master Page from Left Nav.
  4. : Click on Convert an HTML file to a SharePoint master page

enter image description here

  1. : Copy the Master Page Gallery URL From Open Windows For Exm: [http: //XYZ-SERVER /_catalogs/masterpage]
  2. : Map this URL to your Local PC and copy your Theme Folder into this Location.
  3. : Use Step 4 again after copy your folder you will see HTML file in your convert wizard
  4. : Click your Copied Theme Folder and select HTML file and click on Insert Button enter image description here

  5. : It will generate you *.master file for your New Theme (Template)

  6. : Now Click on Edit Master Pages and publish your new Theme File

Now Your New Master page is ready to apply in your sites and SubSites

I Hope this will help full for you.

If You need more information, reply it.

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