i have a 10 year old Macbook and cannot open the books app to store PDFs in it...this comes up. How do I fix it?

Lenburnie61 wrote:

https://discussions.apple.com/content/attachment/3a3fc780-6754-4bea-877b-cf4feba2f525

What happens if you reset the Library...?

Update your device—

Make sure that you're using the latest version of iOS or iPadOS on your iPhone, iPad, and iPod touch, or the latest version of macOS on your Mac.

See if there is anything here—

Read books and more with Apple Books

https://support.apple.com/en-us/HT201478

Apple Books Support