When buying a house in a chain, the deal can fall through at any time, for any reason, up to the point of exchange of contracts. Having your property chains collapsing is a very emotional time, especially as so much time, effort and money will have been spent up until getting to that point. You should, however, find out the exact reason why your chain has collapsed, as it could be salvageable. If the conveyancing process has been slow, some people in the chain may get frustrated and pull out. If there are delays, then speak to your estate agent and put forward a definitive date for the exchange to take place and then work with your solicitor to make sure this is achieved. It doesn't always work, however knowing that the end goal is within sight can help keep the chain together.