# Building OpenTap

**URL:** https://forum.opentap.io/t/building-opentap/903
**Category:** General
**Created:** [October 17, 2022, 2:28pm UTC](https://forum.opentap.io/t/building-opentap/903 "2022-10-17T14:28:37Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![andy1](https://avatars.discourse-cdn.com/v4/letter/a/a8b319/32.png) [@andy1](https://forum.opentap.io/u/andy1)
#### Post date: [October 17, 2022, 2:28pm UTC](https://forum.opentap.io/t/building-opentap/903/1 "2022-10-17T14:28:37Z")

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Hi  
I have an issue with building OpenTap from the GitHub repo on Windows 11 with Visual Studio 2017 as you can see from the screenshot : the build is complaining about CS0170 Use of possible unassigned field ‘Timestamp’ etc

 ![OpenTAP - Microsoft Visual Studio 17_10_2022 15_22_28](https://us1.discourse-cdn.com/flex020/uploads/opentap/original/1X/8495d2ffdef85304757605229fc1a53c6c5ee07c.png)

Thanks Andy

regards Andy

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### Author: ![rolf\_madsen](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@rolf\_madsen](https://forum.opentap.io/u/rolf_madsen)
#### Post date: [October 17, 2022, 2:46pm UTC](https://forum.opentap.io/t/building-opentap/903/2 "2022-10-17T14:46:18Z")

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it seems that your version of the C# compiler is not smart enough to understand that `evt` has a value on on line 27.

I think you just need to use a newer version of Visual Studio or maybe update your .NET Framework SDK?

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### Author: ![andy1](https://avatars.discourse-cdn.com/v4/letter/a/a8b319/32.png) [@andy1](https://forum.opentap.io/u/andy1)
#### Post date: [October 30, 2022, 2:03pm UTC](https://forum.opentap.io/t/building-opentap/903/3 "2022-10-30T14:03:25Z")

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Thanks Rolf  
Sorry for the delay - been off opentap for a week or 2.  
This is a clean install of Visual Studio 2019 CE , everything is up to date .  
Can you point me towards any details of the environment setting (runtimes and .NET frameworks) required for windows to get this solution to compile. Since your reply I have added everything available from the Visual Studio Installer  
Thanks Andy

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### Author: ![rolf\_madsen](https://avatars.discourse-cdn.com/v4/letter/r/43a26b/32.png) [@rolf\_madsen](https://forum.opentap.io/u/rolf_madsen)
#### Post date: [October 31, 2022, 11:53am UTC](https://forum.opentap.io/t/building-opentap/903/4 "2022-10-31T11:53:58Z")

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Hi @andy1,

I am not sure which information to give you, but you can try running

`dotnet build`

inside the OpenTAP source folder.

This requires the .net6 compiler to be installed, but it compiles against .netstandard2.0. (tap.exe is compiled against .net framework 4.8).