Builds randomly ~250MB too small

In the last few months, I’ve started having the problem of almost every second or third build being about 250MB smaller than it’s supposed to be, and it seems to be missing different random things each time based on the fact this missing content results in different bugs at runtime if I try to run the build.

It happens for both platforms I’m building to (PC and Android), and there doesn’t seem to be any way to predict when it will happen. The only solution is to try the build again and check the final size.

This has been happening for several LTS releases in the last several months, the latest of which is 2019.4.34f1.

Does anyone have any clue why this would happen or how to prevent it?

Hm, I wonder if your asset database is corrupted subtly in some way. Have you tried a Reimport All on the project?

Otherwise, try building it again and again and keep track of the build report (google for how) and see if they differ in some meaningful way.

Yes, I’ve done several Reimport Alls since this began happening. That’s because every time I upgrade Unity versions, there are random prefabs that inexplicably break all throughout the project, and the only way to fix them is to reimport them, but since it’s random, I can’t hope to know which ones need reimporting, so the only safe thing is to reimport everything.

But I’ll see if comparing build reports turns up any clues.

Are you using source control? Are you using it correctly? Are you properly source-controlling ALL meta files? The meta files are pretty much the only glue holding anything together in Unity.

Some info about Missing script warnings, GUIDs, renaming GUIDs, etc:

https://discussions.unity.com/t/836322/2
https://discussions.unity.com/t/815173/7
https://discussions.unity.com/t/815173/9

EVERYTHING in Unity is connected to the above GUID. It is super-easy to inadvertently change it by renaming outside of Unity. Don’t do that. Instead:

  • close Visual Studio (important!)
  • rename the file(s) in Unity
  • in Unity do Assets → Open C# Project to reopen Visual Studio
  • now rename the actual classes, and MAKE SURE THE FILE NAMES DO NOT CHANGE!

If you are NOT using source control while you do this, renaming files is an EXTREMELY dangerous process. Use source control at all times so that you can trivially revert if you miss a critical step and damage your project.

Please consider using proper industrial-grade enterprise-qualified source control in order to guard and protect your hard-earned work.

Personally I use git (completely outside of Unity) because it is free and there are tons of tutorials out there to help you set it up as well as free places to host your repo (BitBucket, Github, Gitlab, etc.).

You can also push git repositories to other drives: thumb drives, USB drives, network drives, etc., effectively putting a complete copy of the repository there.

As far as configuring Unity to play nice with git, keep this in mind:

https://discussions.unity.com/t/736093/3

Here’s how I use git in one of my games, Jetpack Kurt:

https://discussions.unity.com/t/807568/3

Using fine-grained source control as you work to refine your engineering:

https://discussions.unity.com/t/826718/2

Share/Sharing source code between projects:

https://discussions.unity.com/t/719810/2

Setting up an appropriate .gitignore file for Unity3D:

https://discussions.unity.com/t/834885/5

Generally setting Unity up (includes above .gitignore concepts):

https://thoughtbot.com/blog/how-to-git-with-unity

It is only simple economics that you must expend as much effort into backing it up as you feel the work is worth in the first place.

“Use source control or you will be really sad sooner or later.” - StarManta on the Unity3D forum boards

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@Kurt-Dekker yes, we have been using Plastic SCM for several years now. The issue doesn’t arise when making any changes such as renaming, moving, etc. It’s usually just when we upgrade Unity versions and it has to reimport assets. When it does, it often breaks random prefabs, some of which haven’t been touched in ages, nor any of their dependencies. There’s no apparent reason at all for why those particular prefabs break.