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Editor freezes at 'Begin MonoManager ReloadAssembly' when starting a Scene after a few times



Steps to reproduce:
1. Open QA-supplied project ("")
2. Open Scene "Login" in Assets -> Scenes
3. Enter Play Mode
4. In the Username field type in:
5. In the Password field type in: unityteam123
6. Exit Play Mode
7. Repeat 3-6 steps for a couple of times (shouldn't be more than 4)

Expected: Editor does not freeze
Actual: Editor freezes

Reproduced in: 2018.3.12f1
Not reproduced in:2017.4.24f1*, 2019.1.0b10**, 2019.2.0a10**

*Required Prefabs break
**Compile errors, can't start the project

The editor seems to freeze at:
"Reloading assemblies for play mode.
Begin MonoManager ReloadAssembly"

  1. Resolution Note:

    The issue stemmed from the user's project leaving a blocked network thread persisting between playmode stop/starts. Once this thread was properly cleaned up between runs the editor freeze no longer occurred according to the user.

Comments (5)

  1. PNUMIA-Rob

    Aug 25, 2020 14:57

    UPDATE: I found this article at where deleting the Library folder was a solution, this has fixed the issue for me and my and my project is now reloading after code edits without locking up. =)

  2. PNUMIA-Rob

    Aug 25, 2020 14:40

    I'm also experiencing the same issue in 2018.4.26f1 :(

  3. webzen_kyunghee

    Aug 20, 2020 02:33

    I'm same issue in 2018.4.26f1

  4. LuisMer

    Jun 30, 2020 10:32

    Facing same issue. Any advice on how to track any persisting thread, or terminate all threads OnApplicationQuit()¿? Thanks in advance

  5. nasir_41

    Jul 10, 2019 06:29

    I'm facing same issue in 2019.1.9f1

    Unity freezes after following editor log when I click play after exiting a play mode on editor.

    Reloading assemblies for play mode.
    Begin MonoManager ReloadAssembly

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