Updated my OS to 10.0.14955.1000 on windows phone yesterday night and since then I am not able to open apps. Whatsapp Hike Microsoft Edge are some of those apps I am not able to open
you have updated to windows insider fast ring which could break many apps and functionalities of your device. It is recommended to perform a hard reset and starting afresh without restoring the backup once on insider fast ring. this should fix your issue, if not then either roll back to public build using windows device recovery tool or wait for future builds.
also if you are incapable to performing a a hard reset now, simply reinstall those apps which are not working.