Installing VS2026 side by side with VS2022 breaks VS2022 iOS MAUI NET9 Development Environment

[mobilewares]

Description

After installing VS2026 side by side with VS2022 - it's no longer possible to run iOS NET9 MAUI apps on Mac via VS2022 as the Pair to MAC installs NET10 maui workloads/tooling and then will only work if XCode 26 is installed (and matching MacOS _version).

Note: I am not clear if updating Mac to XCode26 and MAUI project to use NET10 fixes this - assume it would, but we definitely do not want to be using NET10 for this current project so that's not an option.

Steps to Reproduce

Repro Steps :

1. Start with working MAUI iOS Development environment :
a) VS2022 installed on Windows (17.14.20)
b) Mac OS with XCode 16.4
c) MAUI Project using MAUI NET9
d) Working Remote Simulator to Mac OS machine allowing running/debugging iOS version of App.

2. Install VS2026 with Mobile Development Workloads (hence NET10 framework installed too) (18.0.0 stable)

3. After installation, when running VS2022 with same MAUI NET9 project the following happens :

a) When Pairing to the MAC under VS2022, it remotely installs the MAUI NET10 components and tooling instead of MAUI NET9 versions despite loaded project targetting NET9 MAUI / net9-ios workloads.

b) Attempting to run iOS NET9 MAUI App via remote simulator fails and VS2022 compile output reports error This version of .NET for iOS (26.0.9766) requires Xcode 26.0. The current version of Xcode is 16.4. Either install Xcode 26.0, or use a different version of .NET for iOS.

4. Other symptoms observed too at this point :

a) Project folder reports that NET10 workloads are installed and not the NET9 workloads (via dotnet workloads list command).

b) It's impossible to downgrade the MAUI workloads or manually install workloads in that project folder to NET9 - either install is failing and rolling back. Error message in command window is
Workload installation failed: Workload pack 'Microsoft.NET.Runtime.Emscripten.Node.net9' in manifest 'microsoft.net.workload.emscripten.net9' [C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.workload.emscripten.net9\10.0.100\WorkloadManifest.json] conflicts with manifest 'microsoft.net.workload.emscripten.current' [C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.workload.emscripten.current\9.0.0\WorkloadManifest.json]

c) After pairing, available iOS Simulators list is not showing a bunch of the the simulators anymore - for example no iPhone devices above iPhone14 are coming up.

Expected behaviour :

• VS2026 and VS2022 should work side by side for iOS MAUI development
• The Pairing process on VS between VS and Mac should install the MAUI NET version components/tooling specific to that VS version (ie. VS2022 should install MAUI NET9 and VS2026 should install MAUI NET10).
• (Nice to have) VS2026 also support NET9 MAUI iOS - but not sure if that's possible. VS2026 however appears to still allow running MAUI NET9 Android Apps so this indicates this scenario should be possible too (if VS2026 Pairing installs components based on project MAUI NET version in use).
• The list of Simulators available to the specific XCode version should not be hiding valid simulator devices.

** Current Workaround **

• Completely remove VS2026 (and hence NET10) from Windows PC. After that VS2022 Mac Pairing installs NET9 MAUI Components as per before. However - list of available simulators is still broken/missing - not clear how to fix that up.

Link to public reproduction project repository

No response

Version with bug

9.0.110 SR12

Is this a regression from previous behavior?

No, this is something new

Last version that worked well

Unknown/Other

Affected platforms

iOS

Affected platform versions

VS2022 with iOS NET9 SR12 / Mac with XCode 16.4

Did you find any workaround?

As per other comments - completely uninstalling VS2026 was the only way to restore ability to debug iOS NET9 MAUI App again (however some iOS simulators are now missing from the list).

Relevant log output

[jayhayman-hdd]

Can confirm I've experienced the exact same problem. All of our dotnet 9 builds now fail with VS2026 installed side by side with VS2022. There are no packs/tooling in the XMA/SDKs/dotnet/packs/ for Microsoft.iOS.Runtime.ios-arm64.net9.0_26.0 or Microsoft.iOS.Runtime.iossimulator-arm64.net9.0_26.0.

I have deleted these folders on both Mac and Windows but always restores with dotnet 10 and doesn't pull any of the dotnet 9 build tools.

[pme442]

I can also confirm I have the same problem.

[rmarinho]

Seems the problem is your installation is using the latest net9 workload that needs xcode26. If you want to use a old XCode you need to pin the workload set to use a older version that uses that old iOS version like NuGet Gallery | Microsoft.NET.Sdk.iOS.Manifest-9.0.100 18.5.9227.

https://learn.microsoft.com/en-us/dotnet/core/tools/dotnet-workload-sets

[jfversluis]

Let us know if that works! If it does, either close this or just don't respond and it will close automatically, thanks!

[rmarinho]

dotnet workload install maui --version 9.0.305

I got the workload set version from here https://github.com/dotnet/macios/releases/tag/dotnet-9.0.1xx-xcode16.5-9219

[mobilewares]

dotnet workload install maui --version 9.0.305

I got the workload set version from here https://github.com/dotnet/macios/releases/tag/dotnet-9.0.1xx-xcode16.5-9219

Hi -

As per OP - after installing VS2026 the Windows PC has MAUI NET10 components applied everywhere and any attempts to install MAUI NET9 with --version (directly in the project folder) was failing for me & it would rollback the attempted install. I am pretty sure I tried .305 - also tried 300/200/100 etc versions and same issue.

Here is some error messages shown (after it failed/rolled back) when trying to pin 9.x.100 to the project folder with explicit --version parameter (but had similar for other 9.x versions)

Workload installation failed: Workload pack 'Microsoft.NET.Runtime.Emscripten.Node.net9' in manifest 'microsoft.net.workload.emscripten.net9' [C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.workload.emscripten.net9\10.0.100\WorkloadManifest.json] conflicts with manifest 'microsoft.net.workload.emscripten.current' [C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.workload.emscripten.current\9.0.0\WorkloadManifest.json]

Can you confirm if this is something you actually have working on your machine or if it's just a theoretical suggestion?
If you do have it working can you provide a bit more information such as what order you did this in & which location you installed the 305 release (was it globally or in the project folder).

Similarly, if you have this working - did you end up with scenario where you could run MAUI NET9 iOS Projects from VS2022 against a Mac but also be able to run NET10 projects from VS2026? (excluding iOS NET10 as I do not want to change the MacOS/XCode).

thanks
Niall

[mobilewares]

Additional note :

I would love to end up with scenario where I could use VS2026 for both MAUI NET9 and MAUI NET10 & just pin the MAUI NET workload to each project's folder. I have the 'XCodes' util on my Mac (current MacOS 15.6) so it's possible for me to install XCode 16.4 and Xcode 26 side by side there and switch the 'active' version back and forth there.

[dazzknowles]

For the record it, understandably breaks .Net 8 too.

If like me you were using an Insiders install, you can roll that back to 11201.2 and it will work fine side-by-side with VS22.

Incidentally, I don't think it's safe to update VS22 beyond 17.14.16 either.

[durandt]

b) It's impossible to downgrade the MAUI workloads or manually install workloads in that project folder to NET9 - either install is failing and rolling back. Error message in command window is

Workload installation failed: Workload pack 'Microsoft.NET.Runtime.Emscripten.Node.net9' in manifest 'microsoft.net.workload.emscripten.net9' [C:\Program Files\dotnet\sdk-manifests\10.0.100\microsoft.net.workload.emscripten.net9\10.0.100\WorkloadManifest.json] conflicts with manifest 'microsoft.net.workload.emscripten.current' [C:\Program Files\dotnet\sdk-manifests\9.0.100\microsoft.net.workload.emscripten.current\9.0.0\WorkloadManifest.json]

I get the same error by only installing the dotnet10 SDK om my mac where I am trying to run/develop my MAUI9-app. The time when we have overlapping dotnet versions is painful every year, we should be able to continue working and supporting net9 apps when net10 is released (and should not have to update all projects and solutions simultaneously). I remember the tooling throw a very similar error last year that was not easy to troubleshoot or google for.

[captainjono]

Im getting the same issue using dotnet8, installing latest vsinsiders has bricked my vs22. every project type now fails to load i dont use maui, but i target win/mac/ios/android with my apps using native apis directly. i was trying to investigate the legacy support and plan my apps update to dotnet10 next year. Looks like i should of waited another few more months...

'Microsoft.NET.Sdk' specified could not be found

i dont recall ever selecting "uninstall everything" before installing vs26, but thats essentially what i got.

[mobilewares]

Bump
How do we get some action on this - issue is still sitting as untriaged? It's causing massive headaches for us, currently we can't install vs2026/NET10 on our development environment without breaking NET9/VS2022 (and being unable to support our NET9 MAUI App).