I had some problems with the miner terminating for no reason some time ago. I don't get it with last versions so I suppose it was some core daemon problem. Check you run version 3.0.38. The GPU miner itself is very stable (at least on Windows). It runs for weeks on various AMD cards in 3-card configurations without any problems if you don't overclock it too much.
AMD GPU Solo Miner ：Dev answer
Why after a long time will collapse?
Why long time the software will be no reaction?
What method can solve?
I have the same problem. For the AMD solo version, it will abort after certain time in various rigs.
I use the 3.0.38 in Windows, latest version. I have 8 AMD GPUs, it happens some time on some rigs. They are not overclocked.
I solo mine.