Another effective troubleshooting method is called Follow the cookie crumbs. What purpose does this serve, besides making me want to devour a cookie? Well, this method requires you to go back when the problem first started and work forward from there. You would be surprised how much information you can learn from asking, when did this problem start? Can you help me with my phone, my fun cat app stopped working. Sure. Now what do you mean by stopped working? Well, when I tap on the app, it starts to load and then it crashes. Well, take a look here. Okay, let us try reinstalling the app and see if that helps. It still crashes. I need my fun cat app. Can you help me with my phone, my fun cat app stopped working? Sure, I would be happy to. Can you tell me a little bit more about how it stopped working. Well, when I tap on the app it starts and it just crashes. That is not good. When did it start? Have you changed anything since that time? Well, it worked last night and I was playing around with it until it started to update and this morning it just didn't work. It might have something to do with the update. Let me take a look into it. Okay, it looks like there was a bug in the update. We can roll back to an earlier version and see if that helps. Oh cuddlier peanut, I missed you. The user can give you information about what they remember but the systems you work with can also offer insightful information. In the earlier lessons about operating systems, we talked about logs. Remember that logs are like your system's diary, they keep information about dates and events that happened on the system. You can dig through logs at the exact time that a failure happened and you may find some defining events that could have caused your issue. We will get into logs in more detail in another course. Error messages are super helpful indicators that can point you in the right direction. Lots of times, a single error will be lost in a sea of errors. It is best to start from the very first error which may be causing a cascade of errors. By fixing the root error, you will correct all the other ones in the process. Some errors don't require extra digging, like a 404 not found error. You might see on websites that have been moved or deleted or permission denied error when accessing a protected file. Let's take a look at this log. I see an error message here at the bottom, do you think it makes sense to try and figure out this error message and resolve it? You might find yourself spending all day trying to fix these little holes. Let us backtrack up the log a bit instead. Oh look, we can see where an error first occurred. Let's try to fix this and now our system is not yelling at us anymore.