When one beneficiary doesn't sign his or her Release, it means that none of the beneficiaries can receive their inheritance.
If a beneficiary were to refuse to sign the Release, I would want to know why. Is there an objection to the contents of the financial documents? Is something missing? Does the beneficiary understand that he or she won't get any money until the accounting is approved (either by the beneficiaries or by the court)? Does the beneficiary object to the compensation the executor is requesting?
If you can find out where the objection lies, you can most likely address it. In many cases, a refusal like this is actually a request for more information. For example, say a beneficiary wants to know why the house sold for $450,000, but only $420,000 shows in the bank account. The executor could show the calculation that showed how much of the $450,000 was spent on realtor's commission, legal fees and payment of taxes. The executor could show the cancelled cheques for those expenditures. Perhaps the executor didn't do a very good job of setting out the numbers, or backing them up with receipts or statements.
Many executors who are acting without lawyers or accountants tend to give an "accounting" that is little more than the current bank balance, without explanation of what happened to investments, RRSPs, the deceased's car, etc. If that's what the executor is presenting, he or she shouldn't be surprised at the beneficiary not signing the Release. I wouldn't sign it either.
If the beneficiary is objecting to the amount of compensation that the executor is requesting, the executor might provide a breakdown of how he or she arrived at that number. The breakdown might include the number of hours the executor put in, the number of kilometres driven, or a list of all of the tasks that the executor had to take care of (this is one reason why executors are always advised to keep a diary or journal of all of their actions on behalf of an estate).
If the issue is compensation and a more detailed accounting isn't persuasive, the executor and the beneficiary may negotiate a different amount that satisfies both of them. If that doesn't work, the executor will have to ask the courts to set the compensation by court order. This takes longer and the beneficiaries get even less because the executor's lawyer is paid from the estate, but at least the issue can be resolved.
It's unusual for a beneficiary to simply dig in his or her heels and refuse to sign the Release without giving a reason or stating an objection, but it can happen. In the end, the executor will give up on asking for information that isn't forthcoming, and will ask a judge to approve the accounting.