The password for the computer in Alan Wake 2 The Lake House is right under your nose
The Alan Wake 2 Lakehouse computer password blocks your way within minutes of starting the DLC. And while there's a clear clue explaining what the code should be, it's not easy to find all the numbers you need or work out the order to put them in to access the computer and open the security door. If you're having trouble with it then I've worked out the computer code for you.
The Alan Wake 2 Lakehouse computer passcode is 180738. Enter that when prompted and then you can access the security door controls.
The Lakehouse computer code can be worked out using the security memo on the desk to the left of the screen. The memo explains that the code must be changed daily and should use a permanent set of numbers to start with, followed by some that change daily, but not birthdays or the current date. So that tells us that we need to find a number that would be a good contender for something consistent and one that could change daily.
The calender near the memo provides the changing number, specifically today's information about how the actress Hedy Lamarr was also an inventor who designed a torpedo guidance system aged 38. (We know we can't use the actual date so that big 14 on the calendar can't be used, as tempting as it might be.)
As for the consistent part that doesn't change, if you check the framed diplomas and certificates on the far wall, you'll see a Notice of Appointment that states the Lake House facility was completed on July 18, giving us 18/07.
Combining the Notice of Appointment's 18/07, with the calendar fact's 38, gives us a 180738 code for the Lake House compute. So enter that, unlock the door and be on your way.