Best Practice:

Export/Import Knowledge Bases, Categories, and Articles in batches. Do not attempt to transfer all at once as some KB Articles may be bigger than others and can cause corruption, issues or unintended issues (missing attachments and other items) that are easier to fix in batches then an all or nothing method.

Also, create a local update set prior to starting just in case.

Example:

Need to export Knowledge Base, its Categories and all its relative Articles from SNOWsiteA too SNOWsiteB.

Follow these steps: