Battery saver won't open

[midnightsunset4]

I just installed the update for the preview for developers and my battery saver won't open. I get an error message that says unable to open the app. Anyone else get this and is there a fix or work around?

 

[edwardtkl]

I have got a couple of apps (whatsapp, line, nokia camera, display) that coundnt open, after I update my phone to gdr1. I get most of them (except "display") fixed by reinstalling the app.