Yeah, “sometime”… Still no update in the bug tracker.
Yeah, every single customer who got a new FP2 in the last three months first having to disassemble their new phone obviously is just a minor inconvenience. 
I really like Fairphone, but sometimes I seriously question their judgement regarding priorities.
Thank you for the solution! I ran into the same problem with a new Fairphone 2 and Fairphone Open 18.01.1. The workaround solved the problem for me.
It is somewhat disappointing that this problem was not identified by Fairphone when testing the new module.
+1
I have not yet bought a screwdriver to ‘fix’ my new phone, but I must say this is highly demotivating. Any updates on this?
iFixit sells the correct one (in a package) but its basically standard Philips. Just mind the size.
Unfortunately this is not fixed at the moment. However Fairphone has accepted the reported bug and also recently assigned an internal-issue-number. From this I conclude that they are looking into it and it might be fixed sometime.
Remving the new camera module indeed works. Weird, but at least it solved the issue.
I had the same problem with a new install of Lineage OS. I could not believe it, but this kind of voodoo made my phone encrypt.
Please Fairphone make this bug highest priority! I do not want the FP to become the laughing stock of security experts.
The mid-February patch (20 February, 2018) that was released to fix the random reboots in newer FP2s, fixed this for me.
It didn’t fix the issue for my wife’s new Fairphone. I tried resizing and formatting the data partition but ultimately only swapping the camera module solved it. Didn’t think about just removing it and start the phone without it, though. 
I read this info and as i have since months the problem with lineage that it did not encrypt i tried it again.
The phone is encrypted now!!!
Before, i tried everything you find in the forum with the only exception: Did not remove the camera module.
Sometimes miracles occur!!!
Thanks!
Hello there,
I have updated my FP2 with the latest release, however I still have the issue.
Encryption does not work
I have not tried without the camera module but I will do so.
I just wanted to report that even with the build FP2-gms-18.03.1 release-keys.
the issue is not fixed totally.
It’s the same for me. The bug in the Fairphone bugtracker is still open btw.
I think https://bugtracker.fairphone.com/project/fairphone-fairphone-os-android-6/issue/84 is the bug you are referencing? I’d like to vote for it (and encourage you all to do the same), but I shudder to create yet another account … 
In the bugtracker there are 4 comments of users. For me the 4th one was of special interest because it also confirms my experience in the past with encryption. It confirms that there should also be some kind of randomness or in other words: After many trials it suddenly works.
I had this problem with FP OS, Fairphone Open and also with Lineage.
Maybe it is worth to try very often until the bug is fixed!
I had the same issue, new FP2, I installed Fairphone 18.03.1, encryption didn’t work. I tried several times, also by manually issuing vdc cryptfs ... commands. The final solution was to remove the camera module and then encrypt the phone, then reinstalling the camera.
I would like to add, that in my opinion this is a very serious bug. I just happened to loose my previous phone and the only thing that keeps me sleeping well, is the fact that it was encrypted with a strong password. Also any company which does not have a policy that all mobile devices have to be encrypted is totally stupid. (It’s 2018!)
Also I wondered why is FP2 not encrypted by default? I read the documentation and thought that with Android 6 encryption is enabled by default with a default password so that you only have to change this password. Finally, I am interested to know, whether FP2 uses any specific hardware to store the encryption keys. The article I linked above mentions “Trusted Execution Environment (TEE)”, how to check for that?
Hello. I would like to try this solution, but I am stuck with how to remove the display, i.e. step #3 of:
Thing is: The sliders look kinda different for me, see here:
https://my.flexvault.de/f/8fabc6a79ebd4c5191d6/
I don´t know how to grab them to move them to the inside.
After a three hour attempt this morning with installing TWRP and downsizing the userdata partition, I really look forward to be able to finally encrypt this phone.
You have to remove the whole case before you can move the sliders.
See here for a good disassembly video …
Thank you very much, AnotherElk. This did the trick for me. Its easy when I know it. This phone is brilliantly designed to be taken apart.
Update: /dev/block/dm-0 mounted on /data… whoa, this whole thing works. I finally got encryption to work on a Fairphone 2 with Fairphone OpenOS 18.03.1 with new camera module removed. You are all just wonderful. Without the forum I would have been stuck completely.
As far as i understand, this only applies to phones that launched with Android 6.0 Marshmallow. Fairphone 2 was launched with Android 5.0 Lollipop. (Btw. This is similar to project Treble: New phones launched with Android 8 Oreo must support Treble, older phones can be update to Treble.)
Thanks for the tip, it exactly fixed my issue. Fairphone OS 18.03.1