Ringtone set from a file reverts to default after reboot When I set a ringtone from a file ("More ringtones"), after reboot it reverts to the default ringtone on the pre-set list. How to fix this?

When I choose a ringtone from the pre-set list, it does stay (does not revert to the default one).

The file I select is in Phone storage/Ringtones.

I tried Zedge to set a downloaded ringtone, same effect: after reboot, it resets to the default one. As a workaround, maybe there is an app that would check the ringtone after reboot and set its own one if it has reverted to the default?

Android 5.1 kernel 3.10.65, model Polariod P5025A, not rooted.

The phone has other issues, such as after reboot some downloaded apps (not always, but Opera almost always) disappear from the desktop, so that I have to bring their icons to the desktop again. The downloaded apps are on SD card (probably that's why), but my old phone (Android 4.4 on Samsung, a great deal better than 5.1) did not have any of these problems.
Apps such as Tasker can definitely set the ringtone after device boot. 


Profile: Event &rarr; System &rarr; Device Boot
Task: Audio &rarr; Default Ringtone:


Type: Ringer
Sound: tap lens icon &rarr; choose File Manger app -> select your sound file.



File Manager app should be such app which allow a sound file to be selected as a ringtone. I'm aware of Solid File Explorer and ES File Explorer providing such feature.

If you don't get the option to use the File Manager app, then clear the defaults of Media Server from Settings &rarr; Apps &rarr; All apps (or three dots line &rarr; Show system) &rarr; Media Server &rarr; Open by default &rarr; Clear defaults.