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I have a query about my 13” MacBook Pro 2012 which I installed High Sierra. A day ago little bit water spread on it and my system completely off. Then I opened and clean MacBook. Now it’s working but a serious issue is that when I plugged charger all runs OK. As I unplugged charger my MacBook becomes slow lagging of mouse pad arrow and its open file and folder in long, long time. But, when I plug charger all work fine
This sounds like you have liquid damage on your logic board. You’ll need to remove the logic board to properly inspect it. If you see any corrosion or staining take a picture of it and post it here for us to see Adding images to an existing question
