Is Polarr crashing for you? Help us, help you. If you're able to reproduce the crash, please email us, firstname.lastname@example.org, with the steps needed to reproduce it. Any bug we can reproduce is as good as dead and we'll fix it with the next update.
A quick fix that sometimes helps a crash is uninstalling and reinstalling the app.
If that didn't work, check out the online version of Polarr if it continues to crash and you need to get work done. Editing a photo is easy with Polarr Photo Editor Online. We'll work on a fix for the bug in the meantime.