Duplicate Web part appearing in SharePoint
The case of the duplicate web part in SharePoint has been around for as long as I remember and I came across it just recently in SharePoint online via Office 365. Essentially what happens is you add a web part to a page, in my case I was adding the script editor web part and clicked on save. I refreshed the page and I couldn’t see the web part so I added it again and all of a sudden I was seeing double. I deleted the web part (even though I could only see the one) and re-added it, however when I came to preview the page after saving it, I would be seeing double again.
Luckily, the fix is quite simple when you know how!
Removing the duplicate Web Part in SharePoint
You will need to navigate to the Web Part Maintenance View of a Page Layout. You can access it by navigating to the site page in question and appending “?contents=1” to the URL.
For example, https://gkm2.sharepoint.com/DemoSite/_layouts/15/start.aspx#/?contents=1
As you can see from the screenshot below, the Web Part Page Maintenance is loaded and I can now see the duplicate web part in question. Go ahead, select the checkbox on the left and click Delete.
There are other uses for the Web Part Maintenance page such as your web page not loading due to a faulty web part etc. You can use the Web Part Maintenance page to help isolate and fix your problem by deleting the problematic web part. In most cases, you may not actually know which web part is causing the issue and it will be a matter of trial an error.