I am about to scream...

[ShadowZone]

I just built a very complex (about 500 parts) but extremely cool looking vehicle... suddenly some weird .... happened (part floated freely but was not transparent and red but looked as if it was attached somewhere). I quit the game to stop the weirdness. I launched the game again. Now I can no longer edit my vehicle. It sits there in the SPH but nothing happens when I click on it. Can't add parts to it. Can't offset or rotate parts. Same in VAB. 3 hours of hard work completely wasted.

Yo devs, how about some dev notes about those kinds of bugs... those that really break the game and set the fun level instantly to zero?

Sorry, I had to vent... this just so incredibly frustrating.

[Mister Kerman]

Weird stuff starts happening after about 300 parts in the VAB; I don't know about the SPH. Especially symmetry issues. Hopefully Whackjob pokes his head in here with some tips. I just avoid it by building modestly these days.

[bakanando]

I had this problem too, with detached parts from the ship being 'attached' and unable to delete. Sadly, I don't remember how I fixed it. It was either ctrl+z or deleting the whole section and redo it.

Try launching some other craft directly from the launch pad, sometimes that clears the VAB/SPH.

Posting logs and the persistence files could help finding the culprit too (and fixing your craft).

Yes, it is a frustrating bug but I don't really know how to replicate it. As far as I remember, my ship didn't have that many parts though -less than 150-.

If I remember anything else, I'll post here.

Edit: It seems this is in modded installs, mine is stock and this still happened.

[ShadowZone]

this is in modded installs because a mod decided my rant is a call for support. which it wasn't. it was just a rant. I am going to rebuild that thing from scratch. will be probably quicker than trying to bugfix this.

and yeah, mine is pure stock as well.

[Whackjob]

I've had this happen, but usually only when I get really high in part count. Though my symptoms tend to be huge pieces that I can't add parts to, select, or move.

I hate to say it, but when it happens, I usually end up starting from scratch again. I even tried making a different save every so often, and it always appears that, even if I roll back to a safe save, I quickly run into the same issue again.

I have a vague and unconfirmed suspicion that it happens when the root part of the parts tree gets too long.

[Mister Kerman]

Hah, it's weird having you back Whackjob. Aint nobody gon' leave you alone.

[Deutherius]

Happens to me fairly often, very independent on part count (had it happen in as low as 20 parts), but usually when I try to do weird stuff with symmetry (for example making a wing, attaching it to the body using 2x mirror symmetry, then trying to attach something to one of the wings using the same symmetry. It's usually better to just add stuff to one of the wings and then reattach the whole wing using 2x symmetry)

I have always resolved the problem by hitting save craft, loading the craft, taking off the problematic part and redoing it in a manner that tends to not break KSP so much.

[ShadowZone]

I've had this happen, but usually only when I get really high in part count. Though my symptoms tend to be huge pieces that I can't add parts to, select, or move.

I hate to say it, but when it happens, I usually end up starting from scratch again. I even tried making a different save every so often, and it always appears that, even if I roll back to a safe save, I quickly run into the same issue again.

I have a vague and unconfirmed suspicion that it happens when the root part of the parts tree gets too long.

Thanks for the input! Could you elaborate on the "parts tree gets too long" thing?

I have tried editing the .craft file and manually removing parts I had a suspicion were responsible for the problems. No effect except for some gaps in the vehicle.

[bakanando]

As you said, this is completely game breaking. I was lucky to unmake it, but I don't have a clue as to what saved me. The only thing I remember is I had removed a section (more than one part at the end) of the ship when this happened.

If it happens again try undoing it with control+z to see if it reverts the bug.

[Tweety]

Yet another bug I have encountered. I typically get very annoyed if its in my roleplaying save and just go and vent on another save....(poor kerbals).

Tweety

[Yukon0009]

It did happen to me, but mostly only in 0.25 or lower.

And strangely enough, this sort of bug only bites once in a while; half my craft are 200+ in parts and they have never been affected, including the 900 part ones.