Search Issue Tracker

Fixed in 2018.3.X

Fixed in 5.5.X, 5.6.X, 2017.1.X, 2017.2.X, 2018.1.X, 2018.2.X



Found in



Issue ID




Unity throws out Fatal Error: Callback registration failed kMaxCallback



Unity throws out Fatal Error: "Callback registration failed kMaxCallback" after working with the project for 30 minutes or more. It appears randomly.

1. Actively use Unity for more than 30 minutes

Actual: Unity continues to work
Result: Unity crashes with Fatal Error.

Reproducible with: 2017.1.4f1, 2017.2.3p1, 2017.4.4f1, 2018.1.3f1, 2018.2.0b6

Reproduced on macOS, Windows, Linux.
Bug Report window does not appear.
Scene files are not restored after reopening Unity so all not saved Scenes are lost.

  1. Response avatar


    Jan 04, 2019

    Please file a new bug report If you are still encountering this problem. The error message is a symptom and can be caused by many different areas. The area for this bug has been fixed.

Comments (205)

  1. F514af08d2b5a84baaefb3d94cccfaed?d=mm


    Mar 17, 2022 00:20

    GET RICH WITH BLANK ATM CARD ... Whatsapp: +18033921735

    I want to testify about Dark Web blank atm cards which can withdraw money from any atm machines around the world. I was very poor before and have no job. I saw so many testimony about how Dark Web Cyber hackers send them the atm blank card and use it to collect money in any atm machine and become rich.( I email them also and they sent me the blank atm card. I have use it to get 250,000 dollars. withdraw the maximum of 5,000 USD daily. Dark Web is giving out the card just to help the poor. Hack and take money directly from any atm machine vault with the use of atm programmed card which runs in automatic mode.

    You can also contact them for the service below

    * Western Union/MoneyGram Transfer Hack

    * Bank Transfer Hack

    * PayPal / Skrill Transfer Hack

    * Crypto Mining Hack

    * CashApp Transfer Hack


    Text & Call or WhatsApp: +18033921735

  2. Eef1c1a15738891652847baa5d0422a6?d=mm


    Feb 01, 2022 09:19

    If you are coming to Karol Bagh as a tourist or local and don’t know how to fully enjoy the lively vibrance of the area, then you must go for our escort service in Karol Bagh. It is one of its kind due the 100 % genuine service we provide is the top notch and do not have any match. Our call girls in Karol bagh are very modest and professional in their approach. They know how to take you on a roller coaster ride of enjoyment and pleasure. Call us or visit our online portal.

  3. 9d0d14d49dced816bef3d1a23ae219b4?d=mm


    Feb 21, 2020 09:10

    I Still get this error in 2018.2.21f1.

  4. A6fc986ab7f0eaafedad213af21bf52f?d=mm


    Apr 30, 2019 08:22

    Happened to me many times,v2018.2.3f1

  5. F9033d33caeaaf5c0bd043ac4528862b?d=mm


    Apr 23, 2019 01:01

    STILL HAPPENING IN 2018.2.0f2

  6. 762bc915f22a530e1370c07f9ef6eb32?d=mm


    Sep 13, 2018 13:58

    2018.2.7 Not fixed. What to do? Wait for 2018.3?

  7. E554a28755f5d7c27767063338a43547?d=mm


    Sep 02, 2018 18:11

    This is becoming annoying.
    Happens on a daily basis now, and has for a month or so (using 2018.2.x.
    I never encountered it before 2018.2 (or so rarely I never noticed it).

  8. 0afd0bfcedf6b9f4509f05f71e45df7d?d=mm


    Aug 31, 2018 22:30

    Still the case for me too....

  9. 4ff0f9c8dada5a37a1a83e4c97054f73?d=mm


    Aug 30, 2018 05:09

    Related but unrelated. I get this same crash message in the log in windows standalone build when I run the build when built with 2018.2.5f1 but it works fine when built with 2018.2.3f1

    Callback registration failed. Increase kMaxCallback.
    (Filename: Line: 191)

Add comment

Log in to post comment

All about bugs

View bugs we have successfully reproduced, and vote for the bugs you want to see fixed most urgently.