Is that phone running other projects OK? Any project is going to need to download the executable files from them.

I just swapped projects when tasks all started erroring out. I never got around to looking at the logs to realise the problem was Android refusing to let something download. I suspect, nothing will change unless Yoyo change the way they do things.

Some projects use a 'wrapper' app between BOINC and their main executable - but even then, it's BOINC which does the downloading, and should have the correct permissions.

It can be easier to work out how projects like YoYo are operating by attaching it to a mainstream Linux or Windows machine, where you can examine the downloads and metadata much more easily. Their Android app is likely to work in a similar way, but with the details hidden.

Some projects use a 'wrapper' app between BOINC and their main executable - but even then, it's BOINC which does the downloading, and should have the correct permissions.

It can be easier to work out how projects like YoYo are operating by attaching it to a mainstream Linux or Windows machine, where you can examine the downloads and metadata much more easily. Their Android app is likely to work in a similar way, but with the details hidden.

Thanks Richard. A quick look at files downloading on Linux didn't give me any clues but Yoyo downloads a lot of files! So could easily have missed something, especially as I don't know what I am looking for. I will change things so I don't get so many tasks downloading at once and then have another look later. Number of different files also affected by four different task types out of six tasks.

Edit: I am not hopeful however that knowing how it works will get me any closer to getting it to work on Android and it may be that isn't the problem on my phone at all and it is one of the projects that needs 32bit libraries installed.

This looks normal to me, I just attached Yoyo to a Windows computer:

I didn't spot anything particularly different on Linux but it may be that the tasks sent to Android clients are different in nature. Haven't had time to have a really thorough look yet though.

A couple of things:
1. The Yoyo app is 32bit (it's from 2015). To be able to run on Android, the Android version needs to be 32bit as well as the CPU.
If this runs on the Samsung A10, its CPU is 64bit.

If the Android version is also 64bit, it won't download the 32bit Yoyo app because that won't run anyway.
If the Android version is 32bit, it requires 32bit compatibility libraries to run anything on the 64bit CPU. Those are available for Android, but you can only install them when you have rooted your device and/or run your own Android ROM. Most people cannot.

2. You can check what CPU you have and what mode it runs in by installing AIDA64 from the Play Store. If the CPU says 64bit (runs in 32bit Mode) your Android version is 32bit. And then you can't run 32bit apps via BOINC. Either all work will err immediately, or BOINC won't even download the app. Ask the project for a 64bit app (which I doubt they'll make).

3. Checking the Samsung A10 on GSMArena, it says there are 2GB and 4GB models only, which will most probably mean the CPU runs in 32bit mode and the Android on it is 32bit.