There are generally three possible reasons for the lack of memory indicated by the mobile phone: insufficient running memory/insufficient storage/insufficient storage of the mobile phone. 1. If the storage space of the mobile phone is insufficient, please delete the compressed package and installation package in the file management-classification view, delete or transfer the unnecessary music/video/other materials to the computer to make room for the storage space of the mobile phone, and then try to clean up the cache regularly. Second, if the memory space of the mobile phone is insufficient: 1. Go to Settings-Storage-Preferred Installation Location-Select User Space (mobile phone storage). 2. Move the programs installed in the system space to the user space, and set-Program Management (or Application)-All-Click Programs-Move to the user space. After completing the above operations, you can also enter the file management to delete some useless junk files and data packets, and free up more space. Third, if the running memory is insufficient, the occupation of running memory is related to the number of programs running in the background, the number of caches and the number of downloaded software. In addition, the mobile phone system also occupies a certain amount of running memory and cannot be cleaned. You can now clean up the daemon and cache the observations. After the phone is turned off, press the power button and the volume button at the same time for about 8 seconds to enter the recovery mode, use the volume up and down buttons to select clear cache, press the power button to select OK, and the cache will be cleared. After cleaning, the phone will be restarted, and then we will observe.