Does closing waive a buyer’s right to complain later?

Signing the closing documents does not erase a claim by itself. What matters is what the purchase agreement says about claims after closing, how long the law allows you to start one, and whether you act when you find a problem. Each of those can end a complaint that was valid on closing day, so a buyer is better placed asking about them before closing than after.

What the agreement says

Look for the clauses that decide how long a seller’s statements stay enforceable, whether a buyer who knew of a problem before closing can still claim, and whether the buyer takes the business “as is”. None of that is fixed by statute for every deal, so the wording governs. Ask your lawyer to explain each clause in plain terms before you sign, because changing it later needs the seller’s agreement.

Limitation periods

Ontario’s Limitations Act, 2002 bars a proceeding started after the second anniversary of the day the claim was discovered (s.4), and a claim is discovered when the person first knew, or a reasonable person first ought to have known, of the matters in s.5(1). Business agreements may vary or exclude its periods, with limits on the s.15 ultimate period (s.22(5)). British Columbia’s Limitation Act sets two years from discovery, subject to the Act (s.6(1)). Alberta’s Limitations Act gives effect to an agreement that expressly extends a period, but says one that purports to reduce a period is not valid (s.7), so whether a contract clause can change the time depends on the province.

Québec’s rules on defects

In Québec, the Civil Code makes a seller warrant that property is free of latent defects, and the seller is not bound to warrant against a defect known to the buyer or an apparent one, meaning one a prudent and diligent buyer could perceive without an expert (art. 1726). A buyer who finds a defect must give written notice within a reasonable time (art. 1739). The parties may add to, diminish or exclude the warranty, but the seller can never exempt itself from liability for its personal acts or omissions, and cannot exclude or limit liability without disclosing defects it knew of or could not have been unaware of that affect ownership or the quality of the property (arts. 1732, 1733). Whether these articles reach a particular sale of a business, or of its shares, is a question for a Québec lawyer. See the biggest risks when buying a business and whether you need a lawyer.