Is there any way to file a will in Massachusetts?
There is no way to file a will in Massachusetts before someone has passed. However, some states, such as Washington, allow you to file a will under seal before someone dies. See RWC § 11.12.256.
What is the standard method of ensuring that the will is not lost or
The standard method is having the lawyer who prepared the will hold the original, with the testator having a copy that explains where the original is located. It is also a good (but not common) practice to tell the executor where the will is held.
For those that don't the original with the lawyer, there are a couple options. Read this LegalZoom.com article for some do's and don't on where to store your will: https://www.legalzoom.com/articles/where-to-store-a-last-will.
One place you do not want to store the will is a safety deposit box at a bank--unless another person is on the account and has access to the safety deposit box. Some states' banking laws won't grant access to anyone but the executor of the estate and you can't prove you are the executor until you have the will. So safety deposit boxes can be tricky when none but the deceased is listed on the account.