Project Crashes on load. Full release and video with information. Any help would be great.

Here is the video showing what is in the build and pretty much how it breaks.

Here is a link to download the latest version that I wanted to release this weekend. This is the full dev release of the project. (Keep in mind that it this build is the one that now crashes on load)

I dont mind releasing the entire project as that has kind of been my plan for a very long time. But what I have been running into lately has been a steady increase of blueprints breaking when I close the editor. Pins come unconnected, some random blueprints will become blank and as of today it just outright wont load anymore.

I have also observed that I cannot package the game anymore either. It errors out for some reason.

I have been wrestling with this for a couple weeks now and it seems to be a losing battle.

I am less worried about source control than I am with the fundamental issue of a project that randomly eats itself. I do have many many backups of the project over the last few months I backup the project daily on a cloud.

I need to know how to fix this and how to avoid this problem in the future.

Please, any help or information on this would be great because it really does potentially effect the future of the project.

Do you use any plugins?
Did you edited as last action a animation blueprint or character blueprint? If yes, try to delete this particular asset, or delete the asset or assets you last edited (make a backup).

Hmm yeah I made a change to the base character blueprint. I might try that, but deleting the main character blueprint would be kinda not ideal :confused:

Have you tried deleting the temp folders?


These are non volatile folders that hold backups, autosaves, autogenned files etc etc. It is safe to remove them, however i would keep backups of them just incase.

I tried this and it does not seem to solve the problem. It crashes at 93% still.

If you delete QTController and QTPlayerHUD it loads up again.

I suppose you changed some structures which leads to disconnecting pins.

Since its no c++ you wont be able to fix it as long as the editor crashes :confused:
And avoiding… always check structures pins when changing them and keep making a lot of back ups because something else will take its place :mad:

That is really weird because, I didn’t modify those two files or their structures in the latest version.
This has to be fixed

edit: QTController and QTPlayerHUD dont have structs. What the heck?

They dont?

0]LogBlueprint:Error: [compiler QTPlayerHUD] Error No input structure to break for QTItem Base Struct
0]LogBlueprint:Error: [compiler QTController] Error No input structure to break for QTItem Base Struct
0]LogBlueprint:Error: [compiler QTController] Error This blueprint (self) is not a QTStatusEffects_C, therefore ’ Target ’ must have a connection.
0]LogBlueprint:Error: [compiler QTController] Error COMPILER ERROR: failed building connection with ‘Actor Class is not compatible with PLACEHOLDER-CLASS QTStatus Effects C 46 Class.’ at ItemIsHealth
0]LogBlueprint:Error: [compiler QTInventoryEquipment] Error The current value (/Game/FirstPersonBP/Blueprints/Inventory/Items/Credits/QTItemCredits.QTItemCredits_C) of the ’ Drop Item ’ pin is invalid: /Game/FirstPersonBP/Blueprints/Inventory/Items/Credits/QTItemCredits.QTItemCredits_C isn’t a valid subclass of QTItemBase_C (specified on pin DropItem)

Some Errors from your log.
Maybe you forgot about them ^^

Edit: But you should not have any trouble fixing it then :slight_smile:

Oh they need to access structs from other objects. Pretty much everything else uses structs and parent child relationships.

So a struct from another object can cause a random other file to die?

It sounds like they want to work with data thats not there / not connected, so not random at all.
But i didnt have a further look into your project because there is no point without those two files, so i dont know what the exact problem is :slight_smile:

I have a slightly older version from earlier the same day that will load. I can make that available. I have rolled back to this version twice now and ended up with the same error happening. So its a version right before everything finally breaks.

Download that version right here.

This version will load but it has some other suspicious problems. These problems ARE related to structs, its possible this is what is causing the build to break.

I am not able to package the project anymore… It errors out now, it only started doing this recently.

No matter what I do, every time I close the editor the following files revert back to an error state.


A pin to a struct disconnects every time I close the editor. Cant play until this is fixed. I have now fixed this error maybe a hundred times.


This file resets back to its default state no matter what I do completely breaking all child ammo pickups.


This file forgets its ammo type every single time I close the editor. I have to specify in the drop down that its QTAmmoBullets.

No matter what I do I cannot get these files to save. they revert back to what they were when I close the editor. At least in this build you can actually see the project in action. But as it stands right now, It dies when I make any significant changes.

I see what you mean, have u tried to recreate those blueprints?
Thats what i would do. Dont know what else to do^^

I think what needs to happen is figuring out what is causing the problem in the first place. Then getting it fixed. This project depends on it.

So I had help on the Looter Shooter project! I have some really strange news on the topic. So it turns out that the engine is doing some very very strange things with the blueprints.

For one, all blueprints that are child objects that are considered “data types” are not being recognized by the engine. So I have to open each and every one of these blueprints, turn them into full blueprint and add a node so that they stay as full blueprint files instead of just data types.

So I spent last night opening up a hundred or so different blueprint files and added a random node to the graph that does absolutely nothing just to prevent those files from being ignored by the engine.

In addition to that, a specific file. Inventory\Base\QTItemBase has become a file that will destroy the entire project if I make any changes to it. It is not yet known the nature of the problem. But this file is all kinds of weird right now.

Some serious breakage is going on right now and as far as I can tell, its not something I can directly fix myself. More information and a video coming soon.

So here is a video of me talking in much greater detail about how the blueprints have blown up the project. Its interesting to note that using blueprints for anything of reasonable size is a lot more like navigating a minefield than it should be.

This is not good, if this cannot be fixed it may very well be the death of this project. :frowning:

Download the latest build here:

I never had problems with Structs so far, do you have any links on this?
But at least you some more informations on your problem :slight_smile:

I learned of this new information while speaking with DevilsD as he pulled my project apart to see what makes it tick.

We found a host of very strange things. If you download the build I made available and make a change to the QTItemsbase file you will see the entire project implode and no longer load anymore.

Hi over here :slight_smile:

I’ve worked on medium scale projects with blueprint twice now and I encountered the problems you’re talking about.

First thing I need to say is: I didn’t find a solution to keep the rest of my project other than deleting the damaged asset and rebuilding it from scratch with a different name.

I posted that a while ago: limitations of blueprint.

I’ve also learned quite a lot about that matter in the past months. It is not random. People who are more comfortable with proper coding seem to not be concerned by that so I believe that’s something we’re not doing properly that is causing that problem.

I however thought about it a lot and tried to avoid it. So far it looks okay and I believe it should continue if I keep maintaining the whole thing clean.

  • avoid over complicated circular dependencies (actor A referencing actor B referencing actor C who is referencing actor A again)
  • keep names, blueprint files and folder where they are once you tied them to a lot of other parts of your code
  • do the “blank print” thing on the data-only blueprints to avoid them to disappear
  • make backup every 2 hours (I have a hard drive full of backups from 3 months ago, needs cleaning I know)
  • make a “store value” function in your blueprints to set up their default values rather than using the “default panel” if you’re experiencing any blueprint resetting their custom variable values

So far I don’t have any problems on my new project.

I hope you get your things straight and as you wish them to be, good luck :slight_smile:

This is not uplifting to say the least.

Basically its saying that doing blueprint projects is not feasible because of the engine eating the project. You can make a big list of dos and donts but you lose the entire project if you make even one mistake?

Its not that simple :stuck_out_tongue:
And you did not lose your entire project, you just found a bug or a bad way of doing what you wanted.
That is progress!
Dont get too frustrated, just take one or two days off and recreate (or maybe fixx) the file/s that are broken.