Hey,
I just wanted to package my project for Windows 64-bit and it goes wrong
Here is the end of log:
Please help, I’m on Jam and really running out of time
Thanks 
Hello SiCzech,
I wish I saw this post sooner, I would’ve helped out. I’m assuming the Jam is over now? If not and you still need help, please post the entire log that contains the errors from your project’s directory under Saved / Logs. While the error given is “Unknown Error”, this basically means “It failed” and the actual error/warning causing it is elsewhere in the log.
We haven’t heard from you in a while, SiCzech. Are you still experiencing these issues? If so, could you provide the information I requested? We need more information from you to progress with this issue.
In the meantime I’ll be marking this post as resolved for tracking purposes. Whenever you’re available, please leave a comment and the post will reopen.
Hi, and sorry for my delay, I wasn’t on AnswerHub for long time.
Well, I solved this issue ! I’ve just migrated all maps to another new project, compiled everything and it worked 
But, maybe I’d like to ask about another issue. I’m trying to package my new project on Windows 64-bit but instead of packaging it’s asking me to install Visual Studio which I’ve never used, never needed because all my code is made in BP.! Also I’ve noticed the Project Launcher which I’ve never needed for packaging neither. Could you explain me what is it for ?
Thank you
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Welcome back. Did you add any plugins to your project that may be code based and need to recompiled? That would cause the editor to require Visual Studio to be able to continue.
The Project Launcher is a way to be able to set up profiles for launching/packaging your project so that you can switch between profiles at will. It is often used when packaging DLC or Patches as well. You can find more information here: Preparing Unreal Engine Projects for Release | Unreal Engine 5.1 Documentation
oh…you were right, thank you again…
But finally, I’ve got a problem as I had before, the unknown error. And the migration doesn’t work…
It is a alpha version export of our game
Here is the Log:link text
As I mentioned before, the “Unknown Error” message is never indicative of what is actually wrong. It’s always a good idea to hit ctrl+f and search for the word “Error” when you’re sifting through a log like this. This pointed me toward a couple messages.
The first one is this:
ERROR: NOTE: Please ensure that 64bit Tools are installed with DevStudio - there is usually an option to install these during install
This means that there may be some parts of your Visual Studio install that need to be added. This can be done in the Visual Studio installer, which you can bring back up by selecting it in your Programs & Features section of the Control Panel in Windows. Anything under Visual C++ should be what you need to include.
The second one is:
Assertion failed: Pair != nullptr [File:D:\Build++UE4+Release-4.12+Compile\Sync\Engine\Source\Runtime\Core\Public\Containers\Map.h] [Line: 520]
This error usually means that there is a level reference somewhere that shouldn’t exist or is trying to point a level that no longer exists. This can also include attempting to reference a particular level’s Level Blueprint. Please look out for these and see if you can find the culprit. Based off the context, it seems like it could be in your “kino_button_BP” asset.
ok, I removed the empty variable of my kino_button_BP.
I don’t have Visual Studio installed at all, so shall I install it ?
If you plan to use any plugins that require being recompiled. You shouldn’t need to unless that Error (which is actually labeled as a warning) is stopping you from packaging. Are you still receiving the “Pair != nullptr” error after editing your blueprint?
Hi, so it was because of broken plugin that I installed.
Thank you so much for help