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Bug Project broken after upgrade to new Unity version

Discussion in 'Editor & General Support' started by kraskon, Feb 15, 2023.

  1. kraskon


    Oct 3, 2016
    Hi, I have just upgraded Unity from 2021.3.1f1 to 2022.2.6f1 and I face a very weird behavior: basic physics seems not to work any more, like adding force to a rigid body, colliders, etc. There are no errors, everything compiles and all textures are still visible. Needless to say - everything was working before the upgrade (except scrolling behavior in XR, this was the reason to upgrade).

    Is there a way to like repair the project? I have already reimported all assets, restarted, no change.
  2. Kurt-Dekker


    Mar 16, 2013
    Anytime you leave the LTS stream and enter the tech stream you are an unpaid test pilot for Unity. You may reasonably expect a fair amount of turbulence and problems.

    See section towards the middle related to updating Unity.

    Lost progress / project / work / stuff disappeared in Unity.

    This article is to help you when you have lost significant progress or work in your Unity project.

    It is designed to give you avenues of discovery and investigation.

    It is NOT a guarantee of restoring your lost work. It is NOT a substitute for proper IT / Data security procedures.

    To decide which parts are applicable to you, look for major bolded headings.


    Your project probably is still on your computer. Try a computer-wide search for some unique filenames that you know are in the project you think is gone.

    To start your search, one common file to all Unity projects is named

    Some things that might have happened:

    - you are not opening the project that you think you are
    - you are in the correct project but not opening the same scene you had open before
    - you dragged the project (or part of it) into the trash (intentionally or inadvertently)
    - you moved the project (or part of it) somewhere else (intentionally or inadvertently)
    - an overly-aggressive antivirus solution quarantined it because it saw code being compiled in there
    - you're using a directory sync like OneDrive or Dropbox... NEVER USE THESE SERVICES WITH UNITY!
    - something else??

    As I said, it's probably still all on your system to be found if you look in the right places.

    A typical Unity project will have at a minimum the following folders:



    Close Unity and make a full project backup RIGHT NOW. Do not do ANYTHING else until you back it up 100%.

    Ideally copy that backup to another computer, or back it up to another external hard drive entirely. This is just basic data processing best practices during data recovery operations.

    If you can see all the files and folders of your project, make sure you are opening the scene file you were working in.

    Once you have opened the scene, look in the hierarchy window, select an object and move the mouse over the Scene window and press F to focus that object.

    Additional notes:

    - ALWAYS use proper industrial grade source control (see below)
    - NEVER use Dropbox or any file sync mechanism in Unity.
    - NEVER move files within your project, except by doing it within Unity
    - ALWAYS be sure you are fully backed up before upgrading Unity


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

    EVERYTHING in Unity is connected to the above GUID, which is stored ONLY in the metafile, and hence why the metafiles ALWAYS MUST be source-controlled.

    When Renaming: It is super-easy to inadvertently change the GUID 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.


    You must isolate if there is something wrong with your Unity installation, something wrong with your project, or perhaps just a corrupted import or asset database.

    First, ALWAYS back your project up. Then try deleting the
    folders that are within your project, the directories that are peers to the

    If that doesn't work it is time to bisect. Make a new empty project and get Unity to open that. If you cannot then it is time to fix your Unity installation, either by fully reinstalling or verifying it with the hub.

    Once you have an empty project open, begin copying over your project. Try the entire thing. If it crashes, try half of the project, then the other half, etc.

    As always, if you're using Windows, another "first thing to try" is to simply reboot the system. This often fixes typical Windows issues related to locked files and locked directories.

    ISSUES RELATED TO UPGRADING PROJECTS (eg, changing to a higher Unity version)

    Upgrading to a later version of Unity is a one-way process. Any project that has been updated should NEVER be reverted to an earlier version of Unity because this is expressly not supported by Unity. Doing so exposes your project to internal inconsistencies and breakage that may actually be impossible to repair.

    If you want to upgrade to a newer version of Unity, do not even consider it until you have placed your project fully under proper source control. This goes double or triple for non-LTS (Tech Stream) versions of Unity3D, which can be extremely unstable compared with LTS.

    Once you have source-controlled your project then you may attempt a Unity upgrade. Immediately after any attempted upgrade you should try to view as much of your project as possible, with a mind to looking for broken animations or materials or any other scripting errors or runtime issues.

    After an upgrade you should ALWAYS build to all targets you contemplate supporting: iOS and Android can be particularly finicky, and of course any third party libraries you use must also "play nice" with the new version of Unity. Since you didn't write the third party library, it is up to you to vet it against the new version to make sure it still works.

    If there are issues in your testing after upgrading Unity, ABANDON the upgrade, revert your project in source control and be back where you were pre-upgrade with the earlier version of Unity.

    Obviously the less you test after the upgrade the more chance you will have of an undiscovered critical issue.

    This risk of upgrading is entirely on you and must be considered whenever you contemplate a Unity version upgrade.

    Do not upgrade "just for fun" or you may become very unhappy.


    I'm sorry you've had this issue. 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:

    I usually make a separate repository for each game, but I have some repositories with a bunch of smaller test games.

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

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

    Share/Sharing source code between projects:

    Setting up an appropriate .gitignore file for Unity3D:

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

    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. Digital storage is so unbelievably cheap today that you can buy gigabytes of flash drive storage for about the price of a cup of coffee. It's simply ridiculous not to back up.

    If you plan on joining the software industry, you will be required and expected to know how to use source control.

    "Use source control or you will be really sad sooner or later." - StarManta on the Unity3D forum boards
  3. kraskon


    Oct 3, 2016
    Wow, this was comprehensive :) Thank you!
    I can only reconfirm the importance of source control, and having github free really leaves no excuse not to use one.

    Back on my issue: it is ok, I have lost nothing and I even know how to repair it - by redoing the project from scratch. However, it is bothersome and happens now for a third time out of the last 5 or 6 upgrades. Not every time, which is awesome, but often enough to be pain in the...

    About the "LTS stream" and "tech stream"... not sure how this is meant, but when I install an editor from Unity Hub from the Official Releases section, I would expect it to be stable. Unstable Pre-releases - fair game.

    Unity already reimports the projects when switching between editor versions. So, if I manually can restore my project (worked every time so far), I wonder why the platform cannot do it on it's own?!
  4. Kurt-Dekker


    Mar 16, 2013
    This is where I believe Unity is being at least a little disingenuous with their choices. I see this:

  5. kraskon


    Oct 3, 2016
    Omg... I actually never really saw this differentiation right there...
    Well, thanks again!! :)
  6. kraskon


    Oct 3, 2016
    Just for completeness to add here - after downgrading all problems magically disappeared.
    @Kurt-Dekker, I owe you a beer.
    Kurt-Dekker likes this.
  7. nasos_333


    Feb 13, 2013
    The non LTS versions are not even in beta stage in general, i would just not expect anything stable from Unity at this point after unity 2021.3 LTS be exponentially more unstable than unity 2019, and i wont even compare the non LTS versions, those are only good if you are experimenting imo

    Even in the 2021.3 LTS there is so many massive breaking issues, that can make it unworkable in various ways, from randomly erased projects, to random swapchain related graphics crashes and editor wait times that can take forever, this LTS looks like in some pre beta stage today.

    The last stable Unity i know of that actually worked in all cases was Unity 2019.
    Last edited: Mar 1, 2023