Water damage on Mac book air

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Since this is accidental hardware damage, your Mac needs to be serviced. Contact Apple Support here to learn about repair options: Get Support.

Also, only go to Apple, an Apple Authorized Service Provider, or send your device to Apple for service (if applicable or available). Do not go to a 3rd party or attempt a repair yourself. This is for the assurance of authorized and professional repairs that use genuine Apple parts. Please refer to this from Apple Support:

Beware of counterfeit parts

Some counterfeit and third party power adapters and batteries may not be designed properly and could result in safety issues. To ensure you receive a genuine Apple battery during a battery replacement, we recommend visiting an Apple Store or Apple Authorized Service Provider. If you need a replacement adapter to charge your Apple device, we recommend getting an Apple power adapter.

Also non-genuine replacement displays may have compromised visual quality and may fail to work correctly. Apple-certified screen repairs are performed by trusted experts who use genuine Apple parts.

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The computer needs to be examined by an authorized service center. Liquid damage is often extensive and ongoing due to corrosion.