You need an "OPEN IN SAFE MODE" option!

My son decided to save and exit my project I had up which was in no way ready to be saved and exited. Now I cannot open it at all because it wants to crash since the code to build the level is not in a stable state! There definitely needs to be a “Start In Safe Mode” option that will allow me to open the project without it trying to render it so I can fix the problem that’s happening and re-save it. I’m trying to load different backups, but they’re not working, either.

I am VERY upset right now, because it’s really not that difficult of a fix to get it working again, but I cannot get in there to make the simple fix. Is there anything I’m missing to be able to open this up right now? If not, I’m completely, well, I won’t say that here.


I feel with you my fellow unrealist :slight_smile:

We have had a number of close calls over the year or so too. And not being able to open a project after some stupid little error is one of our biggest fears.
We (my team and I) could live with a manual way to edit the project as well; in fact I fixed CryENGINE projects all the time for the company I worked for a few years ago.

But some sort of “safe mode” to open a project, where for example the execution of blueprints is suspended until the user decides otherwise. This would be awesome and solve soooooo many headaches.

@Moderators: Please add a poll, thank you :slight_smile:

@Mbublitz: You will be the first to know if we come up with anything that might help you! In the meantime, can you please provide the forum with the version of the engine/editor you are based on, as well as log files that may help track down why the editor is refusing to open the project? thanks.

Best regards,


This has happened to me lots.

If you know the BP thats messing with you and it seems like you do, see if there is one in the auto backups folder.
Go into the folder where that bad BP is and CUT it and paste it somewhere on your PC, make sure its outside of the project folders. Replace it with the backup, but make sure the backup has the exact same name. Launch the project.

If that don’t work.
Take the bad BP, start a new project. Drop it into the content folder of the new project. See if you can open it there and fix the problem. Then manually move it back to the original project and see if you can launch it then.
I’ve been able to recover from this each time (except the very first) using backups or opening the BP in a diff project and fixing it.

Thats opening projects with the BP in the content folder. Trying to import uasset files doesnt work.

Yes, taking out the bad BP, opening a new clean project and then moving the BP into the new content folder might just do the trick! Thanks for the reminder :slight_smile:

Still, I very much welcome the idea of a “safe mode” to ease that process xD

I’m trying to recover by creating the clean project, then moving my BP to the new content folder, but since it’s a subclass of my C++ class, I’m running into difficulties.

So far I’ve added my C++ class to the new project with the same name as it was in the old one, but my BP is still refusing to open because it says it “derives from an invalid class.” And if I mouse-over the BP it lists the parent class as “None.” All my other BPs seem to open just fine.

I’ve got the 4.10.2 version of the project that I may have to fall back onto and then redo all my work since then. NOT something I’m looking forward to, since the only reason I switched to 4.11 was because an engine bug was causing problems on 4.10.2 with regards to saving the BP after recompiling the C++ code and after dealing with that error many times, after the last time it just wouldn’t open the project anymore until I migrated it to 4.11.

I’ve done so much since then. Just wish I knew why none of the backup BPs are working. From what I’m seeing on the error message when I try to open my project (“Array index out of bounds: 0 from an array of size 0”) it is just a simple checkbox that is checked that shouldn’t be checked or my number of rooms is set to 0 instead of 1. (This is what I was working on when my son exited it out.) Either way it would get rid of this error if I could just get in there to change one of those variables. I’m trying to reset the defaults in the C++ portion (or returning out of any related C++ functions before they execute any code), but it’s not working. I’m pretty sure the invalid references are coming in through the BP directly and I’m not going to be able to fix it with any code trickery.

This is the specific message on the crash reporter:

Assertion failed: (Index >= 0) & (Index < ArrayNum) [File:D:\programs\Epic Games\4.11\Engine\Source\Runtime\Core\Public\Containers\Array.h] [Line: 785]
Array index out of bounds: 0 from an array of size 0

Here’s something interesting. Just updated to 4.11 preview 3 (was using preview 2) and (magically) my project is opening again! :slight_smile: Didn’t do anything different than to update the engine version (which had the side-effect of rebuilding my game .dll file on first load.)

Anyway, woohoo!!! :slight_smile: Still want that “Open In Safe Mode” option, though.