Unity breaks when opening different version

I am using 5.4.0f3 with a free license on my personal computer, however my university is using 5.2.1f1 with an education license on their computers. When I took my project home everything worked fine, however when I brought it back to my university everything broke. It keeps saying can’t file id, but I can see all my files are here, is there any way to fix this?

Forwards compatibility is not supported in Unity. This means that older versions of Unity can not open projects created/opened by newer versions.

Then it should say so, not open it without a warning and just not work. It also breaks forward compatability as well, because reopening in an older version overwrites some files so that when you open it in the new one again things are still broken. It should have a dialog saying something along the lines of “This is from a newer version of unity, and probably won’t work correctly. Do you still want to open it?” and have a read only option so you can see if it really doesn’t work without borking your project.

People always back up their work regularly, use source control, and for sure always back up prior to opening a project in a tool with a version different from what it was created in. If you expect a software tool to perform perfectly in all situations you’re going to have a bad time.

I do use Git, but the thing is that unity has a version number saved in the files. So it would be simple to implement a warning saying that if the version number is newer, then ask if they want to open it in read only mode. So that you can test compatibility without messing up your files.

You’re not wrong :). Probably more chance of getting the warning rather than adding a read only mode though since anyone can extend the editor - it would likely require a huge amount of effort to continue working with existing editor extensions. But yeah, add the suggestion in issue tracker.

One thing you might try though is just deleting the Library folder in the old version. Often that will resolve these kinds of issues.

At one point I even tried clearing everything that was in my gitignore ( https://www.gitignore.io/api/unity ) and when that didn’t work I tried again, but also deleting the .meta files as well. Which also didn’t work. No matter what I tried with that version it couldn’t find the file id, and I know that all my files were there.