# Editor.exe hangs when using another System.Collections.Immutable.dll version
**URL:** https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698
**Category:** Technical
**Created:** [May 19, 2022, 2:43pm UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698 "2022-05-19T14:43:25Z")
**Posts on this page:** 8
**Page:** 1
### Author:  [@fostyn](https://forum.opentap.io/u/fostyn)
#### Post date: [May 19, 2022, 2:43pm UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/1 "2022-05-19T14:43:25Z")
The Editor.exe hangs after startup if a plugin, in its own folder, uses a more recent version 5.0.x of the System.Collections.Immutable.dll.
Only the kill of the ‘Keysight Test Automation’ process via the Task Manager is possible.
In the \Dependencies folder of the latest OpenTAP, v9.17.4.0, I see that v4.6.26515.6 of System.Collections.Immutable.dll is used.
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### Author:  [@alexander.larsen](https://forum.opentap.io/u/alexander.larsen)
#### Post date: [May 23, 2022, 7:20am UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/2 "2022-05-23T07:20:12Z")
Hi @fostyn
I tested this with OpenTAP 9.17.4 and Editor 9.17.3.
I am not able to reproduce this issue. I see the editor hangs if `System.Collections.Immutable.dll` is missing, but it seems like it works as expected with version `5.0.0`.
Generally, however, you cannot expect everything to keep working normally if you change dll dependencies, becaause they are not guaranteed to be backwards compatible.
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### Author:  [@fostyn](https://forum.opentap.io/u/fostyn)
#### Post date: [May 23, 2022, 8:21am UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/3 "2022-05-23T08:21:30Z")
Hi @alexander.larsen ,
thanks for checking this out.
We use the latest version of both OpenTAP and the Editor, v9.17.4.
Just tested again on a completely new installation in the folder D:\OpenTap.
In a Subfolder D:\OpenTAP\Plugins it is enough to just copy the System.Collections.Immutable.dll (5.0.20.51904, it’s not possible to upload this file).
The Editor.exe starts up, but we can’t select or run anything else… the Editor.exe hangs.
Maybe I wasn’t clear enough, but it wasn’t my intention to replace the DLL(s) from the \Dependencies folder.
Our test was to see what happens if we use other versions of pre-existing DLL’s in our own folder (like DLL’s from the \Dependencies folder) !
We know that this can sometimes cause problems but I didn’t expect that the Editor.exe would have problems with this already at start-up.
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### Author:  [@alexander.larsen](https://forum.opentap.io/u/alexander.larsen)
#### Post date: [May 23, 2022, 11:05am UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/4 "2022-05-23T11:05:38Z")
Hi @fostyn ,
I am copying the exact same version into my installation and I don’t see the error.
I tried with the `net461`, `netstandard1.0`, `netstandard1.3`, and `netstandard2.0` versions of the DLL and everything seems to work fine.
Can you upload your session log from a hanging Editor instance?
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### Author:  [@fostyn](https://forum.opentap.io/u/fostyn)
#### Post date: [May 23, 2022, 11:21am UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/5 "2022-05-23T11:21:17Z")
Here it is:
[00.txt](https://forum.opentap.io/uploads/short-url/dK9xqSfNhBuJw3o8F32wXVE9ktd.txt) (14.3 KB)
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### Author:  [@alexander.larsen](https://forum.opentap.io/u/alexander.larsen)
#### Post date: [May 23, 2022, 1:31pm UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/6 "2022-05-23T13:31:42Z")
Thanks, I am able to reproduce it now!
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### Author:  [@alexander.larsen](https://forum.opentap.io/u/alexander.larsen)
#### Post date: [May 23, 2022, 2:31pm UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/7 "2022-05-23T14:31:56Z")
FYI I have identified the bug in OpenTAP:
>
>
> The RedirectAssembly method was added in 2017 to fix a bug that prevented runnin…g
> tap8 from a tap7 installation, but today it has resurfaced as a bug:
> https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/6
>
> The bug seems to be fixed by removing this legacy workaround
>
> Closes #599
The fix should make it into 9.18
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### Author:  [@alexander.larsen](https://forum.opentap.io/u/alexander.larsen)
#### Post date: [June 20, 2022, 8:51am UTC](https://forum.opentap.io/t/editor-exe-hangs-when-using-another-system-collections-immutable-dll-version/698/8 "2022-06-20T08:51:22Z")
Hi @fostyn,
FYI 9.18 has been released and this issue has been resolved