A group of Microsoft Products and technologies used for sharing and managing content, knowledge, and applications.
Hi Darren,
To move only 50 files from the parent site to the subsite, the easiest way is to use file explorer. I notice you are using new experience of the library. Please check if you can find the View in file explore option via the steps in the following screenshot through IE browser. If yes, please try moving the files via File explorer.
Besides the method above, here are some other methods for your reference:
Method1:sync both of the parent library and subsite library to local, and then move files between them.
Method2: save the parent site library as template -> download it to local -> upload to list template gallery ->create a new library using the template in subsite.
(please refer to the To save the library as a template part under set up a default file template when you create a document or form library in this article)
Method3: use content and structure to move files. (you can find it through site settings ->site administration)
Note: we need toactivate the publishing feature in the site collection level before using this method.
Thanks,
Sky Pei