Hi Markus Richter,
The AI answer is technically correct about the limitation, but it misses the actual modern solution. You are trying to apply a legacy on-prem mindset (SMB shares) to a cloud-native tool (Intune). In a pure Entra environment, NT AUTHORITY\SYSTEM has no network identity. Trying to force it to authenticate to an on-prem SMB share is a dead end.
The Solution: Use Win32 App Packaging (.intunewin)
Stop using the file share for this deployment.
Use the Microsoft Win32 Content Prep Tool to wrap your installation files into a single .intunewin package.
Upload that package directly into Intune as a Win32 App.
Configure the app to install in the System context.
Intune will securely download the installation payload from Microsoft's CDN directly to the local cache of the endpoint. The Intune Management Extension (running as SYSTEM) will then execute the installation locally.
No SMB shares, no network authentication issues, and the end-user needs absolutely zero permissions. Cut the cord with the on-prem share!
Tracy Le