Purchasing a flat where the original sale deed is lost can be concerning, but there are steps to mitigate the risk. The seller can issue a public notice in newspapers detailing the lost deed and their intention to proceed with a sale using a certified copy. After a waiting period, the buyer can also issue a notice confirming their intent to purchase. Notarised undertakings from the seller regarding the property's history and the missing deed are also crucial. While a certified copy and these notices can suffice for establishing title, the absence of the original deed might pose minor challenges when selling the property in the future.