As you know (at least I hope so), when you export a file with the RTC, the file is exported on the service tier. After that you have to DOWNLOAD it on your local computer.
The first time you do that, you are asked what you want to do: download or open it and if you want to continue being asked this.
If you remove the toggle “Always ask before opening a file of this type” (or something like this. I translated it from Italian.) you are never asked anymore what you want to do.
And if you want to change this behaviour?
You need to delete something in file C:\Users\<USERNAME>\AppData\Roaming\Microsoft\Microsoft Dynamics NAV\PersonalizationStore.xml
Search for this tag:
And remove it.
Before saving the file, remember to exit the RTC.
Next time you export the file, you will be asked what you want to do.