As I wrote in my post yesterday, you can file a caveat with any Supreme Court of British Columbia registry before probate is granted if you intend to dispute the validity of a will.
What if you are not disputing the validity of the will, but wish to apply to vary the will under the Wills Variation Act? (In British Columbia, you may apply to vary a will on the grounds that adequate provision has not been made for you by your spouse, common-law spouse or parent.)
I have sometimes come across instances where someone making a claim under the Wills Variation Act files a caveat in a court registry. In my view, this is not appropriate. The purpose of filing a caveat with the court registry is to prevent the executor from getting a grant of probate without a trial to determine whether the will is valid. A Wills Variation Act claim is not a dispute over the validity of the will, and there is no reason for a Wills Variation Act claimant to delay probate.
Of course, if you believe that the will is invalid, and also wish to make an alternative claim under the Wills Variation Act to vary the will if the court finds that the will is valid, then you may file a caveat.