leave/let well alone
let well alone
To refrain from changing, disturbing, or becoming involved in something so as to avoid unintentionally causing (or worsening) problems. To be honest, you're better off letting well alone at this point. She's so angry that anything you say will just make things worse. Messing with the registry can cause catastrophic problems for your computer. If it isn't already totally busted, I would let well alone.
leave well alone
If you leave well alone, you do not interfere in something, because it is all right as it is and you might make it worse. He knew when to leave well alone and when to interfere. Gordon knows his business, he says, and I should just leave well alone.