Cause analysis
1.Android system mobile Phone only supports apk format files, other format files can not be installed on the phone.
2. Sometimes it may be a software problem we can try to download and install the software again.
3. There may be a mobile phone problem, we restore the phone factory settings can be
4. The most common problem is that the Android phone has limitations. We didn't open the source. We just need to select it.
Solutions.
We found "apps" on our phones (Android phones are usually called).
2. Then find the "Settings" menu in this area (different phones may be set to different names, but Samsung phones are called).
3. Then we find "more".
4. In the more open interface we will see a "safe" click on it to enter.
5. Here we will have an "unknown source" below the page, as long as it is selected to install the Third-party software.
6. Pop-up "Unknown source" prompt, click "OK".
7. As shown in the picture, choose it:
OK, now we go to install the software to see if it can be normal installation Ah, this is an Android phone security settings Oh.