If you have a Samsung Galaxy phone you may well have seen an error message flash up reporting that 'Unfortunately Samsung Galaxy has stopped'. Here's how to fix appcrashes and clear an app's cache in Android. 

'Unfortunately X has stopped': What does it mean? 

The error message itself is self-explanatory. It means an app has crashed. Also see: How to permanently delete unwanted apps: free up space on your device by getting rid of unnecessary apps 
So you could just relaunch the app, but what should you do if you keep seeing the same error message? 

How to fix 'Unfortunately Samsung Galaxy has stopped' error message 

We're using 'Samsung Galaxy' as an example here because we're aware of it being a particular issue of late. However, you might see the same error message regarding other apps, in which case you can simply follow the steps below substituting Samsung Galaxy for your troublesome app. 
'Unfortunately Samsung Galaxy has stopped' is clearly a software issue, which can often mean you will be encouraged to perform a factory reset. For many people this has solved the problem, but in doing so you will also lose any not-backed-up data and your customisation options. 
Instead, uninstalling and reinstalling an app or clearing its cache will usually solve the issue of apps crashing without you performing a factory reset. Also see: How to update Android 

How to clear an app's cache and fix app crashes in Android 

Step 1. Open the Settings menu and choose Application Manager. (On non-Samsung phones open the Settings menu and choose Apps.)
How to fix 'Unfortunately Samsung Galaxy has stopped' error message
Step 2. Tap the All tab, then look for and tap on the troublesome application - in this case 'Samsung Galaxy'. 
How to fix 'Unfortunately Samsung Galaxy has stopped' error message
Step 3. In this order select Force Stop, Clear Cache, Clear Data. 
How to fix 'Unfortunately Samsung Galaxy has stopped' error message
Step 4. Restart the phone and all should be well.