Hi Hmaltz,
According to the error message “Access Denied”, the command couldn’t be run due to the permission issue.
“Run as administrator” is a troubleshooting step to check the permission of the program. I am sorry for the confusion this has been caused.
Moving forward, when running the command “Set-OwaMailboxPolicy -Identity OwaMailboxPolicy-Default -AllowedMimeTypes '.bmp', '.gif', '.jpeg', '.png'” , the error message you received is very necessary for further troubleshooting. The error message and the PowerShell prompt is a good clue. Therefore, the screenshot was requested in my previous post.
To upload the screenshot in the forum, you can refer the steps below:
1. Click “Use rich formatting” under the text box.
2. Click “Insert Image” icon to upload the screenshot
3. Browse to the location of the screenshot to upload.
4. Click “Insert”.
5. Click “Post”.
Thanks,
Monica Tong