Sometimes, you’re unable to save a list that contains a lot of data as a template. Below, I’ll show you step-by-step how to save a template with 16,000 list items.

1. Go to List Information and click on Save list as a template:
2. Type Filename, template name, and template description then check the Include Content check box and click the OK button.
3. Your site will generate an error message as shown below:
4. Go to Central Admin and navigate to Central Administration, then click Application Management, Web Applications, and then select General Settings:
5. Change the Maximum Upload Size default setting to 1024MB then click OK.
6. Save the list as a template again.