@Ranne, Juuso
We cannot restrict file types to be uploaded to an Azure File Share. It is possible to create Windows ACLS which gives different read and write access to individual accounts. It sounds like you are wanting something like file screening which is available in File Server Resource Manager but is not compatible with Azure Files. You can always leave feedback and request this feature on our Feedback Forum. These forums are monitored by our product teams and allow customers to vote on popular ideas.
Hope this helps! Let me know if you have further questions or issues and I will be happy to assist.
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