In this case you will need to use the “Forgot Password” feature and reset your password.
Mojang will email you a new password and then you should be all set.
In the case you need to “Log Out” (see image below) and try logging in again.
If this also fails then you must have forgotten your password.
When Minecraft first launched, they used your IGN as the username.
It will be loaded. [main/DEBUG] [FML/]: Enqueued coremod llibrary [main/INFO] [Launch Wrapper/]: Loading tweak class name fml.common.launcher. Launch Class Transformers(Launch Class Loader.java:279) ~[launchwrapper-1.12.jar:?
FMLInjection And Sorting Tweaker [main/INFO] [Launch Wrapper/]: Loading tweak class name fml.common.launcher. No Class Def Found Error: org/apache/commons/compress/utils/IOUtils at net.ilexiconn.llibrary. Runtime Patcher.transform(Runtime Patcher.java:43) ~[llibrary-1.5.0-1.7.10.jar:?
All modpack authors have permission to add LLibrary to their pack. If you're a modder and interested in using LLibrary, you can go to the LLibrary Wiki for guides on how to use most of its features. First of all, it adds the mod name of the selected item to tooltips.
In 1.7.10, it also adds the modid and registry name when advanced tooltips are enabled. This is a small notification on the bottom of your screen. Every user with LLibrary 1.2.0 installed can see these.