Cant set modern page as home page !

[Hervé Doher]

Hello guys, i need your help !

I have migrated an old MOSS 2007 sharepoint to sharepoint online office 365 with sharegate tool last year.

I have discovered that when I create a new site or sub site, no problem i have the new modern page.
The problem is on the existing site and the subsite, when i modify the root page for example its still an old web page. if i create a new page, it creates an old page too
How can I convert thses old page to new ?

[#2]

@Hervé Dohercomprehensive guidance on how to transform from classic to modern can be found in the articles under below URL: 

https://docs.microsoft.com/en-us/sharepoint/dev/transform/modernize-classic-sites

For pages the following article provides a detailed description of the possibilities:

https://docs.microsoft.com/en-us/sharepoint/dev/transform/modernize-userinterface-site-pages 

Especially the PnP modernization framework might be interesting for you to have a look at:

https://github.com/SharePoint/sp-dev-modernization/tree/dev

Hope this helps!

[#3]

@Paul Pascha 

My actual home page is in this librairy : "page"
What I have when i set a modern page as default home page for root site  ( stored in page site librairy )

The specified homepage is incorrect. (This site uses managed browsing, so should the homepage be a publication page belonging to the same site.

[#4]

Hi,
Review in the site collection features you have the SitePages feature enabled so you can create modern pages in your site

[#5]

You didnt understant i can create modern page so the feature is actvive @Juan Carlos González Martín 

The problem is i cant set a modern page as default root page.
Watch the  screen shoot i put in the post before.

this is the error I have when i want to change the home page : 
The specified homepage is incorrect. (This site uses managed browsing, so should the homepage be a publication page belonging to the same site.

[#6]

Apparently your site uses Managed Navigation which requires the homepage of your site to be a Publishing Page as the error message states. You could try to disable Managed Navigation (under Site Settings - Navigation) and retry setting the home page. You then have to reconsider your navigation options.

[#7]

@Paul Pascha 

No way if i change to structural navigation, it will be a disaster for performance in sharepoint online.
I was in this mode before - just after the migration ) and sharepoint makes more than 7 seconds to charge a web page ! performance are very very bad ...

[#8]

I'm not telling you to switch to structural navigation. There are alternatives to managed navigation in modern experience as discussed for example in the article below:
https://docs.microsoft.com/en-us/sharepoint/plan-navigation-modern-experience

[#9]

But you said : You could try to disable Managed Navigation (under Site Settings - Navigation)  @Paul Pascha 

I cant find this option.

[#10]

The navigaton settings are under "Site Settings --> Navigation" (_layouts/15/AreaNavigationSettings.aspx). You can only disable Managed Navigation by switching to structural navigation. In order to prevent the performance issues you've mentioned you can make sure the checkboxes for "show subsites" and "show pages" are unchecked. You shouldn't experience performance issues now even with Structural Navigation enabled since you configured SharePoint not to render anything by unchecking these boxes. At this point you can change your site's homepage but your navigation obviously changed (a lot). You should consider and plan for the use of hubsites with their associated navigation mechanism as described in the last article I refered to.

[#11]

I have made some test :
create a new site collection => the default web page is in "page site" librairy
create a new page ( modern ) saved in the same librairy => right clic set as default home page
It works without any problem with managed navigation

in my actual collection site, the default web page is not in "page site" librairy but " page" librairy.
And its impossible to change it.

@Paul Pascha 

[#12]

Finally my expert for sharepoint found the solution ! 

Its was here : 
_layouts/15/AreaNavigationSettings.aspx
then "open the tool term" in the middle of the page 
In taxonomy sharepoint term => deploy collection site then on the root site, second tab navigation

modify the URL by the new modern page !