Give more space to website databases in Safari on Mac
You can use some websites to create and edit documents that are saved on your computer — for example, a travel log about your latest vacation. When you save the document, the website uses space on your computer to store your document as a database.
By default, a website can use up to 5MB of space on your computer. If more space is required, Safari asks you to allow more space. If you don’t allow more space, the website may not be able to save your information.
To see a list of websites that store information, including databases, on your computer, choose Safari > Preferences, click Privacy, then click Manage Website Data.