Can’t be reproduced!
Are there really bugs that can not be reproduced? I am finding it highly doubtful. Mostly bugs that are seemingly unreproducible are simply bugs that are taking more time and effort to be locate appropriately. This is more of a prioritizing question actually, whether you have just the time to track all the bugs and if the activity is necessary.
But, if you as a tester, are finding a professional challenge in locating such bugs this post is for you as it will provide you with several important tips for no bug to escape fixes. Let’s begin with forgetting words like ‘Not reproducible’ and rather use ‘hard to reproduce’ as such a statement is closer to the actual matter of things.
And that! And this also thing! Generally speaking you are to always be attentive while performing testing. Observe the application’s under test behavior as if your survival depends on it. You never know when will a bug pop (although you may presume it to, based on experience, but that is a foul approach as you will be less into exploring the code and more into locating things you know will be there)out and especially if it is one of those hard-to-reproduce ones. Always keep an eye out for any fishy processes occurring in the system. Anything may be considered as a clue. Tiny things like the status bar being in progress for quite a while, additional logs added, anything. Those are your trail made of breadcrumbs.
Your experience may be a good thing as well
Although, as mentioned before, relying on experience may be harmful in particular situations you were not gaining it for nothing, right? Thus you are already aware of certain patterns or sittuations causing similar bugs to appear. Use that knowledge if you have witnessed and reproduced one of the bugs we are talking about before.
Use pen & paper
Noting steps you are taking is a great thing for any tester to do. Such an approach has many positive results without even mentioning ways it makes reproduction easier. When you are noting things you are memorizing them way better, you have specs for future use and many more. Handwriting is a tester’s friend!