Add-AppxPackage : Deployment failed with HRESULT: 0x80073CFF, To install this application you need either a Windows developer license or a sideloading-enabled system.

[0xrpj]

[Erisa]

Make sure you are following this instruction to delete some files:

DELETE (APPXMETADATA, APPXBLOCKMAP, APPXSIGNATURE, [CONTENT_TYPES])

And enable this

[0xrpj]

Been there, done that. Still the problem persists.

[Erisa]

Did you delete all the files and folders specificed? (APPXMETADATA, APPXBLOCKMAP, APPXSIGNATURE, [CONTENT_TYPES])

And are you using Windows Powershell rather than Powershell 7 (which doesnt work)

[0xrpj]

Yes, I did delete it. And yes, I was using windows Powershell. Will try Powershell 7.

[Erisa]

Powershell 7 is the one that doesn't work, my bad for the wording.

[Erisa]

Final thing, did you uninstall the Store version of WSA before doing this?

[0xrpj]

Yes, otherwise it would give me an error saying already installed.

[Erisa]

Gotcha, not sure then. Sorry.

[0xrpj]

I had to unzip the selected package right? Not any others?

[Erisa]

Yes, just that one, And then take out the imagess, run them through the script and put them back again.

I notice in your screenshot the files that are supposed to be deleted are still there,

[0xrpj]

The result is the same even after removing all the msix packages.

[0xrpj]

Is there any way to install the package without running the command:

Add-AppxPackage -Register .\AppxManifest.xml

[Erisa]

The result is the same even after removing all the msix packages.

Those are not what I mean.

You need to delete AppxMetadata, [Content_Types].xml, AppxBlockMap.xml and AppxSignature.p7x or this error will appear.
In your image, all of those files are still present.

[0xrpj]

Oh, I thought it was to be deleted from msixbundle only and not msix package.

It did install but,

[ADeltaX]

I see now, it's the wrong msixbundle. It seems that the newest with everything is only available through Slow/Beta channel.
The size of the bundle should be around 1.2GB, version 1.7.32815