I have Sony Xperia v3 and I always get the error "Storage space is running low. Some system functions may not work." What should I do to solve this problem?
This question is way too broad and was asked to death, general consensus is
- remove applications and media you don't need, if you are rooted remove unused system apps
- move as much applications to sd-card
- install a cleaning application (like clean master), they can make a difference
- use cloud applications such as dropbox to sync your heavy files across multiple computers and devices, why store all those >5MB pictures you've taken on your limited device if your Hard drive has much more capacity?