Answer 1: When installing the program, a parsing package error occurs. A common reason for this is that the installation package is not completely downloaded. You can compare the size of the downloaded apk package with the normal package size. Confirm (generally the error file is only a few KB). If this is the case, it is recommended to download it again when the network is stable or download it from a different computer and then reinstall it. Answer 2: The program cannot be installed. The program cannot be installed for the following reasons: 1. There is a problem with the installation package, such as incomplete or inconsistent signature. In this case, you can try re-downloading and then installing, or use the optimization master to uninstall the original program. Reinstall; 2. The system has protected some programs and cannot install updates by itself. In this case, you may need to uninstall before continuing the installation; 3. The storage space is full. Clean the system garbage and reclaim the storage space. Answer 3: Some programs cannot be uninstalled. If it is a system program, the phone needs ROOT permissions to uninstall it. What I mean is that some malware can crack the ROOT of mobile phones and implant the software into the system program folder. At this time, ordinary program managers cannot uninstall it.