@ooGDoo Thanks for posting in our Q&A. For this issue, did you mean that the app is already in the device, but when you deploy the app as win32 app, it is still installed? If there is anything misunderstanding, please correct me.
To clarify this issue, we appreciate your help to check if the existing app's msi code is same as you configured in the detection rule. Please refer to the following link to get the msi code:
https://stackoverflow.com/questions/29937568/how-can-i-find-the-product-guid-of-an-installed-msi-setup
Note: Non-Microsoft link, just for the reference.
If there is anything update, feel free to let us know.
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