Hi, today I’ve tried to launch the Epic Launcher, but the error AC-001 or something like that has prevent me to launch the program. Then I’ve redownloaded the launcher and before finishing the install everytime write the message “there was a problem with the install, rolling back” or similar, this is the third time.
I really need a launcher that will not go every time for no reasons XD
The engine itself is safe, it has not been deleted lucky for me, but I wanted to download a new engine version and got stuck with the launcher 
What I can do for avoid autoupdating or problems? Do you have any solution?
I reply myself, auto redownloaded launcher (different and latest version) and began to work again, I think that you have to reinstall everytime the launcher, but is not risky? I mean I had to remove my vaultcache and engine version directories, otherwise the launcher don’t delete all directories?
I have try to install the latest engine version, and the launcher throw the error on installing “IS-PQE1223”, is very defective XD
However for those that have this problem don’t worry, the engine is in the epic games folder, select your downloaded version, and go to binaries/win64 and ue4editor.exe (make a shortcut and place in desktop for easy reference 
If the launcher decide to fail to start, you can always remove and install (only the launcher), but first for avoiding redownload all the contents, backup your vaultcache.
Hope that this will help someone in the future, thanks for the help XD!
Hi thunder_nemesis,
I’m sorry that you are having an issue with the Epic Games Launcher. In order for us to offer the best support, we have recently modified the process for how Epic Games can help troubleshoot your Launcher issue. Please visit http://help.epicgames.com/ for technical support, here you can find information and solutions for common issues, as well as a contact form if you still need additional assistance. To access the contact form, please use the “Email Us” button under the “Contact Us” section. Thanks!
In the future, please give up to four days for a response. If after four days you have not heard anything, feel free to bump the thread once. In this case you didn’t really bump the thread as you provided additional information each time, however the four days gives people time to respond to the thread in question.