I recently got myself a new Android phone, not because I wanted to but because the old one was no longer a phone - wouldn't use phone signals.
Coincidentally, the new one has version 6 on it, and that version has the facility to treat an SD card as phone memory - but I recently found out it doesn't work properly. I installed the Kindle app; it installed fine but wouldn't start up for more than a second or two.
I also found out that it's possible to force the system to put an app in internal memory, from the apps section of the system settings. I did that with the Kindle app and the problem went away.
There is a similar problem with BBC Weather; install this on an SD card and you can't put the BBC Weather widget on the screen.
So: If you are having problems with an app on an Android 6 phone, force it onto internal memory and the problem might well go away.
Coincidentally, the new one has version 6 on it, and that version has the facility to treat an SD card as phone memory - but I recently found out it doesn't work properly. I installed the Kindle app; it installed fine but wouldn't start up for more than a second or two.
I also found out that it's possible to force the system to put an app in internal memory, from the apps section of the system settings. I did that with the Kindle app and the problem went away.
There is a similar problem with BBC Weather; install this on an SD card and you can't put the BBC Weather widget on the screen.
So: If you are having problems with an app on an Android 6 phone, force it onto internal memory and the problem might well go away.