# Com-register-event-callback fails, is the myssink.dll component not compatible with windows 10 or office 2016?

**URL:** <https://racket.discourse.group/t/com-register-event-callback-fails-is-the-myssink-dll-component-not-compatible-with-windows-10-or-office-2016/4034>\
**Category:** General\
**Created:** [November 30, 2025, 11:34am UTC](https://racket.discourse.group/t/com-register-event-callback-fails-is-the-myssink-dll-component-not-compatible-with-windows-10-or-office-2016/4034 "2025-11-30T11:34:09Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![subdudu](https://avatars.discourse-cdn.com/v4/letter/s/cdc98d/32.png) [@subdudu](https://racket.discourse.group/u/subdudu)\
**Post date:** [November 30, 2025, 11:34am UTC](https://racket.discourse.group/t/com-register-event-callback-fails-is-the-myssink-dll-component-not-compatible-with-windows-10-or-office-2016/4034/1 "2025-11-30T11:34:09Z")

</div>

I need to control excel's behavior when I use excel doing some task. I run this script:

```scheme
#lang racket
(require ffi/com)
(define app (com-create-instance "Excel.Application"))
(define wbs (com-get-property app "Workbooks"))
(define book (com-invoke wbs "Open" file-path 0))
(com-set-property! app "ScreenUpdating" #t)
(com-set-property! app "EnableEvents" #t)
(com-set-property! app "Visible" #t)
(define ex (com-make-event-executor))
(define thd-save (thread (lambda () (let loop () ((sync ex)) (loop)))))
(com-register-event-callback book "AfterSave"
                             (λ (Success) (Workbook_AfterSave Success))
                             ex)

```

However, this script throws an error: advice: failed (8002000b; invalid index). In Racket's documentation, it states that registering COM events depends on the `myssink.dll` component. Could this component be incompatible with the operating system or Office components? I am using Windows 10 Enterprise LTSC and Office 2016.