Does opening your device void the warranty? Usually not.

You have probably seen the sticker: a small foil seal across a screw or a seam, printed with words to the effect that the warranty is void if it is removed. Most people read that as a rule. In the United States it is closer to a bluff.

The law that changes the answer

The Magnuson-Moss Warranty Act is a federal law from 1975 that governs written warranties on consumer products. One part of it deals directly with this situation. A manufacturer generally cannot condition its warranty on you using its own branded parts or its own authorised service, unless it provides those parts and that service free of charge, or it has applied for and received a waiver from the Federal Trade Commission.

Waivers are vanishingly rare. In practice, if a company is charging you for parts or labour, it cannot also require that you buy those parts and that labour only from them as a condition of honouring the warranty.

The FTC has publicly warned manufacturers over exactly this practice, telling them that tying warranty coverage to branded parts and authorised service is inconsistent with the Act. Several companies changed their warranty wording afterwards. The FTC’s own guidance on repair restrictions, linked at the end of this guide, sets out the agency’s position.

What a manufacturer can still refuse

This is the part people get wrong in the other direction. The Act does not make warranties unconditional. It shifts the burden.

If you replace your own battery and later the screen fails for an unrelated reason, that screen claim should still be honoured. If you replace your own battery, damage the display cable on the way past, and the screen then fails, the manufacturer can decline that repair. The distinction is causation, not the fact that the device was opened.

So a denial is legitimate when the company can point to a specific link between the outside work and the specific fault. A denial is not legitimate when the only reasoning offered is that a seal was broken or a non-branded part was found somewhere in the device.

How to challenge a denial

Ask one question in writing, and keep it narrow:

Please identify which part of my repair caused the fault I reported, and explain how that determination was made.

That single sentence does more work than a page of argument. It moves the conversation from policy to evidence, and it creates a written record. Send it by email or through the support portal rather than by phone.

If the first-line agent cannot answer it, escalate. Ask for the decision to be reviewed by a supervisor or the warranty escalation team, and reference the Magnuson-Moss Warranty Act by name. Companies train front-line staff on policy scripts; escalation teams tend to know the legal position.

If the manufacturer will not move

You have three practical escalation routes, in rough order of effort:

1. Your state attorney general’s consumer protection office. Free, and a complaint often produces a response when a support ticket did not.
2. The FTC complaint portal at reportfraud.ftc.gov. The FTC does not resolve individual disputes, but patterns drive enforcement.
3. Small claims court. Limits vary by state, typically a few thousand dollars, and you usually do not need a lawyer. Magnuson-Moss also allows a successful consumer to recover attorney fees in some cases, which is why companies often settle before this stage.

Before you open anything

Two pieces of practical advice that are worth more than the legal theory:

Photograph the device before you start, including the seal and the screws. If there is a later dispute about what condition it was in, you want a timestamped record.

Keep the original parts. If a manufacturer claims your replacement caused a fault, being able to reinstall the original component and show the fault persists is close to unanswerable.