Safe Mode
Not to be confused with dic:recoverymode
Safe Mode lets you boot up your phone without any third party apps. Sometimes you might end up in Safe Mode automatically, but you can also do it manually to check whether an issue you are having is software related.
Note: On FP1 the popup doesn’t say you’ll reboot into safe mode, it only says “reboot”.
Another option to get to safe mode is to power off your device and, while powering on again, hold down volume up and volume down until the phone has finished booting.
You know you are in Safe Mode if the words “Safe Mode” are written in the bottom left corner of the screen.
In some cases accounts get lost after safe mode. If you are rooted, back up your accounts with titaniumbackup.
[1]: https://forum.fairphone.com/t/fairphone-forum-dictionary/5309/21?u=paulakreuzer
Official page for FP2, FP3, FP4: