Unity keeps freezing when modifying scripts in Play mode

Too often during development, I forget to stop a running scene in the Editor when editing scripts with MonoDevelop (or another editor, it's the same result). Unity consistently(*) freezes and I have to kill the process - and of course I lose all local scene changes at the same time.
The only way to prevent this freeze is if I realize it quickly enough after switching back to Unity from the script editor, and stop the game before Unity finishes compiling the modified script.

Is this a problem with my installation, or is this known behaviour? If the answer is, "don't edit scripts while a game is running", that solution is, quite simply, not good enough. An application I pay for shouldn't crash during normal work flow, no matter what I do to it I have 2-3 freezes/crashes like this every day, and every time I lose work.

Is there a way to prevent these freezes?

BTW, I am using the Windows version of Unity Pro - it seems a colleague of mine doesn't have this freezing problem with his Mac verion.

(*) of course, trying to reproduce this deliberately to generate a testcase doesn't appear to be trivial, since not *every* edit causes a freeze - sometimes it works and I can continue to use Unity (although it usually gets confused, so it isn't really "live editing" and I have to stop and restart the game - but at least it doesn't crash in these cases).

Thank you very much,
Regards,
Wolfram

 

We don't seem to have an entry for this in the bug database, so it would be great if you could file one (even if you can't always reproduce the bug). Does it happen with specific projects or randomly with any project?

 

Ah, sorry, somehow I didn't get notified about your post.

I just submitted a bug about this (Case 395657), please tell me if you need additional infos.
I'll try again to create a testcase for this, although the problem seems to appear only when I'm NOT trying to deliberately reproduce it... ;-)

 

I don't get a freezing on Win7 64 either, but if you change scripts while the application is in play mode, you will get the console total bombed with exceptions right away with a weak computer if the console is open without collapse this could easily lead to a freeze alike behavior

 

Good idea, but that's not the cause. Unity freezes immediatedly, completely, and with 0% CPU usage. In cases where there is no freeze (for example when I was trying to construct a testcase), I can see the console being bombed, but that doesn't pose a problem on my machine.

 

A good way to freeze unity is to have accidental loop in the scripts. By loop, i mean sophisticated version of while(true){};
It works reliably, it is easy to implement and it never fails.

 

True, but it doesn't matter what I am changing in the script (which obviously worked before, since the editor *is* in Play mode and responsive), even minor changes. Just to trigger a recompile seems to suffice to cause a lock up.

Even modifying scripts that are not used in the scene that's currently running cause the freeze.

 

I too am experiencing this problem. In my case it has occurred after I had a bluescreen of death crash, not sure if you had the same wolfram?

I've uninstalled/reinstalled and removed the files from %APPDATA%\Unity, but still the problem persists.

 

I had this problem but I'm pretty sure mine was related to some C# specific socket code. I have a socket open listening for UDP data and for some reason it seems to get stuck open, perhaps my destroy method isn't called. If I release the socket Unity seems to wake up again.

As you can tell from the rather vague description I haven't looked into it in any detail. Playing with the socket (or the program sending the data) seems to clear the freeze.

Maybe that will be a useful lead

 

well, i now have this problem in 2018 wiht unity 2017.x. sometimes, changes don't affect it. sometimes, they do. i don't like doing testing out what is causing this, because restarting unity is a pain in the butt.

 

hello from 2020, where this is still a problem

 

Checking in from 2021.
Just started today, resetting via git isn't helping.

 

possible regression as same happens in 2021.2.1f1 on macOS
this one is extremely annoying and renders the editor almost unusable

 

2021.1.22f1 it's still doing it, that is if I edit a script (and save it) while in play mode, I can never switch back to the editor as it is in a "Not Responding" state.