"Site names cannot contain certain reserved words" when you create a new SharePoint Online subsite
When you try to create a new SharePoint Online subsite, you receive the following error message:
- Site names cannot contain certain reserved words and cannot begin with an underscore. Please enter a different name.
To work around this behavior, follow these guidelines:
Use a different name for the site collection.
Use a site name that doesn't begin with an underscore.
Create a subsite from another site instead of from the root or parent site by using a path that isn't a reserved path. Reserved paths are listed in the "More Information" section of this article.
This issue occurs because certain paths are reserved in SharePoint Online when you create a subsite on the root or parent site collection. For Office 365 subscriptions (excluding Office 365 Small Business), the following paths are reserved, and users will encounter the error when a site is created at these locations
For Office 365 subscriptions (excluding Office 365 Small Business):
In Office 365 Small Business:
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