I am confused on how i should be editing master pages on site collection & sub sites.now i have a team site collection inside sharepoint 2013, and when i check its master pages inside SP designer i found the following, where seatle.html is missing:-

so i enable the "SharePoint Server Publishing Infrastructure" site collection feature and then i refresh the mater pages list where the seatle.html appear :-

now inside the team site i created a new subsite of type team site also, then i opened the new sub-site inside SP designer . But i could not find seatle.html. and now i need to modify the master page for the sub site, so i did the following:-

1. i copy/paste the seatle.master.
2. then i define the new master page as the default and custom master page.
3. then i edit the new master page and i did the modification

now my team sub site had the modification without any problem.

but i have the following questions on the above:-

1. why the site collection will not have seatle.html unless i activate the site collection feature?

2. for the sub-site , seems there is not any way to have a seatle.html for it , so is my process of copying the seatle.master and do the modification inside the new seatle.master copy a correct approach.

3. now inside the team site collection which have the "SharePoint Server Publishing Infrastructure" feature enabled, i copy/paste the seatle.master but when edit the copy and try to save it i got the following error :-

server error: this file may not be moved,delete,renamed or otherwise edited

so why i was able to edit the seatle.master copy inside the subsite, while i could not do the same inside the site collection ?

Hi,

You are seeing the expected behavior. Let me explain.

1. HTML Master Pages such as seattle.html are only available and used when Design Manager is available. Design Manager requires and is a part of the publishing infrastructure. Therefore you need publishing enabled to be able to use HTML Master Pages, otherwise you will edit the standard .net master pages (seattle.master).

2. Related to question 1. Sub sites will not have the web scoped publishing feature enabled by default, thus they too do not allow for Design Manager. You can activate the web scoped publishing feature, or using powershell you can have a sub web inherit its master from its parent. Or once you activate publishing you can then use the browser to have a subweb inherit its master page from its parent.

3. Once you have design manager, i.e. publishing is enabled, seattle.master is now controlled by SP assuming that the corresponding HTML Master page has association enabled (found in the properties of the HTML Master Page). This means you may now only edit the HTML Master page, i.e. seattle.html. If you had instead copied seattle.html to the sub web's master page gallery, SP would not have thrown an error and would have automatically updated the sub web's seattle.master for you.

I hope this helps.

Hi,

You are seeing the expected behavior. Let me explain.

1. HTML Master Pages such as seattle.html are only available and used when Design Manager is available. Design Manager requires and is a part of the publishing infrastructure. Therefore you need publishing enabled to be able to use HTML Master Pages, otherwise you will edit the standard .net master pages (seattle.master).

2. Related to question 1. Sub sites will not have the web scoped publishing feature enabled by default, thus they too do not allow for Design Manager. You can activate the web scoped publishing feature, or using powershell you can have a sub web inherit its master from its parent. Or once you activate publishing you can then use the browser to have a subweb inherit its master page from its parent.

3. Once you have design manager, i.e. publishing is enabled, seattle.master is now controlled by SP assuming that the corresponding HTML Master page has association enabled (found in the properties of the HTML Master Page). This means you may now only edit the HTML Master page, i.e. seattle.html. If you had instead copied seattle.html to the sub web's master page gallery, SP would not have thrown an error and would have automatically updated the sub web's seattle.master for you.

I hope this

Hi John,

Never deal with customized subsite master page at a subsite level before so I looked into it as well.  Activating the "SharePoint Server Publishing" site feature doesn't show the html files in SP Designer neither but they do show up in the Master Page Gallery through Site Settings.  I have a custom master page at the site collection level but I don't see it in the subsite master pages in SP designer, but again, can be found in the Master Page Gallery.  

This leads me to believe that all master pages were intended to be stored at the root level so the subsites can consume them.  We do not see them in SP Designer but copying over your own html to a subsite will work as well. 

It comes down to management/maintenance preference on whether to have all your master page html files at the root level or at the subsite level. It looks like the root level is more Out of the Box way and less considerations on future migration.

Hi John,

1. Correct.

2. I try to always have sub webs inherit their master page from their parent so that I only have to maintain one master page per site collection. Since you are not seeing the HTML Master Pages created for you, then you would have to edit the .master in the sub webs if you wanted a particular sub web to have a custom master page.

3. Trick question. MS best practices are that you never customize the master page anyhow, in particular the seattle.master or seattle.html for that matter. At the least, you should create a copy and edit that.

That all being said, it is important to understand the difference and relationship between a Master Page (.master) and a HTML Master Page (.html). The .master pages come from .net and into SP from at least SP 2007 then into 2010. In 2013, SP introduced the Design Manager and the idea of a HTML Master Page. Only Master Pages or HTML Master Pages and their corresponding .master Master Pages are then allowed in 2013, assuming you have publishing enabled.

The thing is that SP does not actually use the HTML Master Page, it only uses .master Master Pages. What I mean is that when an actual content page is generated for a browser, SP can only use .master Master Pages and .aspx Page Layouts. The concept of a HTML Master Page is now you have a HTML file that you could conceivably load and edit in any web editor tool such as dreamweaver.

But as I mentioned, SP actually needs .master files, so design manger takes a HTML Master Page and automatically creates and maintains a .master for you. To do this, SP must lock you out of the .master and only allow you to edit the .html file.

As with any file in SP though, HTML Master Pages and .master Master Pages are tied to a content type. You could create a file in the master page gallery, then change its content type to HTML Master Page. Once you do this, SP will automatically generate a .master for you (assuming the HTML Master Page could be successfully parsed).

Getting back to your 3rd question. Yes, you could edit the seattle.master directly in a sub web assuming that it does not have a corresponding HTML Master Page. If the sub web is configured to use this Master Page, then changes made to the .master will be reflected in that sub web. If you wanted to do this though, I would first create a copy of the seattle.master, set this as your default master page, and then make your edits in this personalized copy.