How to retrieve data if you forget the BitLocker key disk?

Solution 1:

It is not impossible to recover the data, but it is beyond the capability and resources of most people.

To recover the data you MUST recover key, and if you have lost the key itself, you will need powerful computers and lots of time to attempt to recreate the key. Like, super computers, and even then it'll take lengths of time best measured in lots of years, to recreate the key. Clarification: by lots of years, I mean more years than you have to live, even if you were just born yesterday, AND taking into account likely medical advances.

For the average person, working with the average data, this is just out of the question. This is why there were multiple strong warnings when you applied Bitlocker to the drive about copying and backing up the key.