Apple 6p doesn't know why the SMS memory is so large, but all my messages have been deleted.

Method one

Double-click the Home button of the iPhone device to manually clear the cache in the system, and you can close redundant processes to release memory without any plug-ins or restarting the device.

Method 2

When the iPhone is restarted, once the device equipped with iOS system is restarted, the cache will be completely emptied, and there is no need to double-click the Home button and other cleaning operations.

Method 3

Upgrading the system again will automatically fix some bugs that cause the iPhone to run out of memory. However, the new features of the new system will also increase the burden on iOS, and bugs may appear in the new version. Users can make SHSH backup before upgrading, so as to make full preparations for restoring the system.

Method 4

Resynchronize applications, music and videos. If there is a problem during iTunes synchronization, files that are not completely synchronized to the device will reduce the device space; Resynchronization will automatically clean up incomplete junk files and free up more system space.