We understand that you are having troubles with an External USB device interacting with the Folder Shield feature of your Trend Micro Security. Allow me to share some ideas and help you with this.
The Folder Shield feature continuously checks for programs that are modifying a specific file (this is how ransomware behaves with encryption). This might be the case where you are having troubles with.
To help, you may disable the Folder Shield Protection on USB drives only. But take note, whenever you are not using USB device that you are having troubles with, we highly advise that you enable the protection back again.
To disable, kindly open the Trend Micro Console then proceed to the Data tab.
Then click on the Configure button on the Folder Shield Feature.Proceed as usual then just uncheck the highlighted option as shown below.