Can't Flash LineageOS

[rootboi]

Flashing LineageOS in TWRP fails with an error:

Can't install this package on top of incompatible data. Please try another package or run a factory reset.
Updater process ended with ERROR: 7
Error installing zip file `/sdcard/Download/lineage-14.120170626-UNOFFICIAL-FP@.zip'
Updating partition details...
...done

Here is what I did:

• Installed the Fairphone Open 17.06.04
• Enabled root in the dev option.
• Flashed the latest TWRP by @z3ntu using the apk from here
• Flashed the TWRP with OTA fix file
• Queued the migration zip BEFORE the lineage build.
• Flashed the most recent lineage build from here: https://fp2.joutubes.nl/builds/full/

Any tips on what to do now?

Edit: looks like I am doing rubber duck debugging here on you all. Sorry about that…

I should have done a factory reset first. Now it works.
I hope my mistake helps other people in the future stuck in the same place.

[snevas]

If you come from FP Open, don’t do anything with the migration zip, but follow the instructions under “When coming from any other OS”:

LineageOS 14.1 with OTA updates for FP2

Good news: Thanks to @chrmhoffmann the LineageOS build is now official. Follow these instructions to migrate from this UNOFFICIAL OTA release to the official one: If you are a new user wanting to get the official release and coming from Fairphone OS (or another OS) follow the official instructions: https://wiki.lineageos.org/devices/FP2/install

Old instructions to get on the UNOFFICIAL Lineage build

In a effort to make updating to the latest version of LineageOS easier we’ve setup the foll…

You need to backup and factory reset in stead.

[snevas]

Sorry, didn’t read your last 2 sentences. Glad you made it work