The symptoms of the issue are twofold: either the editor simply crashes on startup (because of the corrupt character BP) or it loads with Error Failed import: SkeletalMeshComponent/ArrowComponent/CharacterMovementComponent which causes the skeletal mesh to disappear on the character BP.
I managed to dig up a much older version from backup that at least loads, but each time I try to move forward and add new features the blueprint inevitably gets corrupt, so there’s no way out. This is when I took a closer look at the components screen and realized that even my older versions were in fact corrupt! Below is a screenshot from an older version of my character blueprint where the details panel of the skeletalmesh/capsule/arrow are completely blanked out! This symptom is the beginning of the debacle, once the BP reaches this stage it inevitably spirals into a corrupt/crash-prone version
I’ve resigned to the fact that I need to build my 587 KB blueprint from scratch again but in the meantime I thought it would be good to see how many people are still seeing this. The general trend I’ve seen in my project is that as it grows larger it becomes more and more prone to crashes/corruption. According to the first thread I linked from Answers it seems Epic is no longer able to reproduce the issue in their internal build but AFAIK it is not clear what fixed it or which release the fix will be targeted for (correct me if I’m wrong on this)
Appreciate your help
PS: I’m currently using 4.4.3 (As for 4.5 I only have the preview version but I’m not able to even convert my project to 4.5 as conversion crashes/fails).
Thanks Cindurion, it does look very similar, did you also get import errors on charactermovemetn/arrowcomp/skeletalmesh during project startup along with the mesh disappearance?
For now I managed to salvage an old version of my character BP that doesn’t look totally corrupt and I’m clawing my way back using that. I was actually planning to get 4.5 only some time down the line but that will have to change of course if this fix is indeed there I did notice in the first Answers thread that someone reported the issue even while migrating from 4.4 to 4.5 as well.
I have 4.5 preview but I’m having some problems in project conversion which is down to either corrupt blueprint(s) or the Substance plugin in my project. (For those curious I did replace Allegorithmic’s 4.4 Substance plugin with the 4.5 plugin on their site but project conversion crashed and I wasn’t sure if it was Substance or any of the numerous BP corruption issues already in my project).
Edit: BTW I came across this wonderful thread Blueprint pitfalls and death traps and the death trap being alluded to in that thread (casting to custom BP class in a macro) is exactly what I was doing around the time when my corruption issues began. I’m staying away from Macros and Function Libs for now!
I just wrote this answer in another thread, but it fits here too. I know you don’t want to hear this, and I know that the engine crashing is really frustrating. The good news is that you can avoid losing lots of work the next time this happens (because IT WILL HAPPEN AGAIN in your life! Over and over again, with every tool!)
Files go bad. Hard disks crash. Computers get stolen. Ideas don’t work out as intended. This is the nature of software development, and you need to always be able to get back to a previous version of anything.
I highly recommend using some kind of source control. Create a git repository at the top of your project, add a .gitignore that excludes all built resources/directories, and then do a git add/commit every so often (AT LEAST daily) to save versions of what has changed. Might want to git push to a remote repository as well, to save against hard disk crashes.
True, I’ve been enormously guilty of using ‘manual’ version control for months now. Switching to something like Perforce/GIT has been on my to do list forever. This was a good lesson after all, looks like I needed a push to finally do the right thing
I can say with confidence that blueprint size is not an issue. My generator is at 14MB and still chugging along fine. Well I am pretty sure the editor response time is somewhat slower, but it doesn’t inherently cause crashes.
I don’t know what is causing your issues, but I am assuming you ran into a few obscure bugs that have hopefully been fixed. Pretty much the main reason I keep the editor up to date. It may break some things moving to a new version, but it saves time later when you hit that bug that the devs can’t replicate on the newer versions.
Good news! I migrated to 4.5 (official, not preview) and I’m not seeing the issue any longer! It’s been so robust so far I went ahead and removed all the clumsy workarounds that I had put to prevent the engine from crashing and reinstated all problematic macros/func libs/cast nodes that were causing issues earlier. So far so good - I’ve only had one crash so far (marquee selection on a bunch of BP nodes) but overall everything’s great in 4.5
I also found a workaround for the Substance plugin crash issue that prevented me earlier from migrating to 4.5 (both preview and official are affected). For anyone else using Substance and affected by a crash during migration, see this thread for the official fix from Allegorithmic - Substance Plugin 4.5.0.0 Released - Engine Source & GitHub - Unreal Engine Forums
Just one more point on the subject of version control that was brought up earlier - Blueprint corruption issues seem to creep up very quietly and only manifest themselves at a point much later in the future so even with version control you’d still potentially need to redo a lot of work if the point of corruption happens in a very early version but only triggers when you try a specific piece of functionality (similar to what was described in the “Blueprint pitfalls and death traps” thread I linked above). Anyway, based on what I’ve seen so far in 4.5 I have my hopes up for a smooth BP-ing experience again!
I did notice in the first Answers thread that someone reported the issue even while migrating from 4.4 to 4.5 as well.