How to fix 401 error after applying a custom master page to SharePoint
This is a short article but it can save you precious time when you apply a custom banding to your SharePoint site.
After applying a custom master page to the site some pages or all of them may start displaying a 401 error, this happens on collaboration sites and system pages namely Team Sites where you have minimal download strategy feature activated.
![Fix SharePoint 401 error](https://handsontek.net/images/SharePoint/401/401.png)
This feature is active by default in this sites but if you will be using custom master pages is a good practice to deactivate it.
On Publishing sites, it’s deactivated by default so you will not experience this issue.
Solution
- Apply back the Seattle master page, even though your site is displaying a 401 error you are still able to access to the master page gallery using this url
/_layouts/15/ChangeSiteMasterPage.aspx
As an alternative you can open the site with SharePoint designer, open the master page gallery and with a right click in the Seattle master page define it as the Default and Custom master
- Go to Site Settings Manage Site Features
- Deactivate the Minimal Download Strategy feature, don’t forget to deactivate it for all the site where you will be using the custom master page
- Go to Site Settings Master Page and apply your custom master page again
No comments yet