My cloud flow looks like this.

The problem is that i want to pass the base64 string from a pdf attachment to my desktop flow. As you can see, the Get Attachment actions produce a variable of content bytes that contains a string.

When i try to pass this string into a variable it seems that the previous string is converted to something like this

So, how can i pass the first string into my desktop flow in order to create the file with the action "Base64 string to file" ?