Why won't apps open on my Lumia 1020?

[Windows Central Question]

I have had my Lumia 1020 for 13 months and recently it has been running very slowly. Now apps won't open - I click on them and get a black screen with 'loading...' in the middle. Either they take so long to load that my phone ends up on the lock screen or they fail to open and it goes back to the start menu.

This happens about 60% of the time and is getting very frustrating. Any help would be much appreciated.

 

[RobinPaul]

Might have to do a backup/reset/restore on your phone (this will also make you phone faster as it will delete old system files and temp files). just a suggestion.

 

[xandros9]

Try a soft reset if you haven't already: The Windows Phone 8 'soft reset' key sequence