MacBook telling me something

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Use the referenced post to restate your issue using the points in the post as a guide.

Details matter

caquc wrote:

So my Cousins MacBook air (2015) say’s “macOS need’s to make change’s” or something like that i dont remember so please tell me what to do?

So make the changes or do something like that.

This is all that can be suggested for you to do given the information you provided. Heed ku4hx's very good advice and post some details and context.